feat!: Remove useCaip25Permission feature flag and enable behaviour by default (#3413)

This removes the `useCaip25Permission` feature flag for the
`SnapController` and enables the CAIP-25 behaviour by default.

## Breaking changes

- The `SnapController` no longer accepts the `useCaip25Permission`
feature flag.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Removes the `useCaip25Permission` feature flag and always grants
`endowment:caip25` when a Snap requests `endowment:ethereum-provider`,
updating tests accordingly.
> 
> - **SnapController**:
>   - Remove `FeatureFlags.useCaip25Permission`.
> - Always add `endowment:caip25` (with `authorizedScopes` caveat based
on selected network) when `endowment:ethereum-provider` is requested in
`#getPermissionsToGrant`.
> - **Tests** (`SnapController.test.tsx`):
> - Update install/update tests to expect CAIP-25 without feature flag.
>   - Remove tests covering the disabled-flag case.
> - Adjust test setup/options to drop
`featureFlags.useCaip25Permission`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
bd0c978. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: Mrtenz

packages/snaps-controllers/src/snaps/SnapController.test.tsx

@@ -5990,7 +5990,7 @@ describe('SnapController', () => {
       snapController.destroy();
     });
 
-    it('grants the `endowment:caip25` permission to a Snap with `endowment:ethereum-provider` if the `useCaip25Permission` feature flag is enabled', async () => {
+    it('grants the `endowment:caip25` permission to a Snap with `endowment:ethereum-provider`', async () => {
       const rootMessenger = getControllerMessenger();
       const messenger = getSnapControllerMessenger(rootMessenger);
 
@@ -6026,9 +6026,6 @@ describe('SnapController', () => {
         getSnapControllerOptions({
           messenger,
           detectSnapLocation: loopbackDetect({ manifest }),
-          featureFlags: {
-            useCaip25Permission: true,
-          },
         }),
       );
 
@@ -6072,7 +6069,7 @@ describe('SnapController', () => {
       snapController.destroy();
     });
 
-    it('grants the `endowment:caip25` permission when updating a Snap with `endowment:ethereum-provider` if the `useCaip25Permission` feature flag is enabled', async () => {
+    it('grants the `endowment:caip25` permission when updating a Snap with `endowment:ethereum-provider`', async () => {
       const newVersion = '1.0.2';
       const newVersionRange = '>=1.0.1';
 
@@ -6132,9 +6129,6 @@ describe('SnapController', () => {
         getSnapControllerOptions({
           messenger,
           detectSnapLocation: detectLocationMock,
-          featureFlags: {
-            useCaip25Permission: true,
-          },
         }),
       );
 
@@ -6205,71 +6199,6 @@ describe('SnapController', () => {
       controller.destroy();
     });
 
-    it('does not grant the `endowment:caip25` permission to a Snap with `endowment:ethereum-provider` if the `useCaip25Permission` feature flag is disabled', async () => {
-      const rootMessenger = getControllerMessenger();
-      const messenger = getSnapControllerMessenger(rootMessenger);
-
-      rootMessenger.registerActionHandler(
-        'PermissionController:getPermissions',
-        () => ({}),
-      );
-
-      rootMessenger.registerActionHandler(
-        'SelectedNetworkController:getNetworkClientIdForDomain',
-        () => 'mainnet',
-      );
-
-      rootMessenger.registerActionHandler(
-        'NetworkController:getNetworkClientById',
-        () => ({
-          configuration: {
-            chainId: '0x1',
-          },
-        }),
-      );
-
-      const { manifest } = await getMockSnapFilesWithUpdatedChecksum({
-        manifest: getSnapManifest({
-          initialPermissions: {
-            'endowment:page-home': {},
-            'endowment:ethereum-provider': {},
-          },
-        }),
-      });
-
-      const snapController = getSnapController(
-        getSnapControllerOptions({
-          messenger,
-          detectSnapLocation: loopbackDetect({ manifest }),
-          featureFlags: {
-            useCaip25Permission: false,
-          },
-        }),
-      );
-
-      await snapController.installSnaps(MOCK_ORIGIN, {
-        [MOCK_SNAP_ID]: {},
-      });
-
-      const approvedPermissions = {
-        'endowment:page-home': {
-          caveats: null,
-        },
-        'endowment:ethereum-provider': {},
-      };
-
-      expect(messenger.call).toHaveBeenCalledWith(
-        'PermissionController:grantPermissions',
-        {
-          approvedPermissions,
-          subject: { origin: MOCK_SNAP_ID },
-          requestData: expect.any(Object),
-        },
-      );
-
-      snapController.destroy();
-    });
-
     it('does not grant the `endowment:caip25` permission if the Snap does not have the `endowment:ethereum-provider` permission', async () => {
       const rootMessenger = getControllerMessenger();
       const messenger = getSnapControllerMessenger(rootMessenger);
@@ -6305,9 +6234,6 @@ describe('SnapController', () => {
         getSnapControllerOptions({
           messenger,
           detectSnapLocation: loopbackDetect({ manifest }),
-          featureFlags: {
-            useCaip25Permission: true,
-          },
         }),
       );
 

packages/snaps-controllers/src/snaps/SnapController.ts

@@ -707,7 +707,6 @@ type FeatureFlags = {
   allowLocalSnaps?: boolean;
   disableSnapInstallation?: boolean;
   rejectInvalidPlatformVersion?: boolean;
-  useCaip25Permission?: boolean;
 
   /**
    * Force any local Snap to be treated as a preinstalled Snap.
@@ -4414,10 +4413,7 @@ export class SnapController extends BaseController<
    * @returns The permissions to grant to the Snap.
    */
   #getPermissionsToGrant(snapId: SnapId, newPermissions: RequestedPermissions) {
-    if (
-      this.#featureFlags.useCaip25Permission &&
-      Object.keys(newPermissions).includes(SnapEndowments.EthereumProvider)
-    ) {
+    if (Object.keys(newPermissions).includes(SnapEndowments.EthereumProvider)) {
       // This will return the globally selected network if the Snap doesn't have
       // one set.
       const networkClientId = this.messagingSystem.call(