fix: Recover missing permissions for preinstalled Snaps (#3775)

Due to a bug in the mobile client, some users may have preinstalled
Snaps with out-of-sync permissions (or no permissions at all). This PR
implements mitigation that checks the permissions for every preinstalled
Snap during initialization and re-grants / re-revokes any out-of-sync
permissions.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Validates and automatically restores out-of-sync permissions for
preinstalled Snaps at init, updating subject metadata and adding
targeted tests.
> 
> - **Snaps Controller**:
> - After handling preinstalled snaps, validates each preinstalled
snap’s expected permissions and calculates diffs.
> - Restores missing/extra permissions via
`PermissionController:grantPermissions`/`revokePermissions` and
refreshes metadata with `SubjectMetadataController:addSubjectMetadata`
(icon recovered from preinstalled files when available).
>   - Logs a warning and captures an exception when restoration occurs.
> - **Tests**:
> - Added recovery tests for out-of-sync preinstalled permissions (with
and without icon).
> - Updated preinstalled snap tests to stub `grantPermissions` and
adjusted expectations (call orders, lifecycle hooks indices).
> - Enhanced `clearState` flow tests to revoke all permissions and
verify re-grant on reinstallation of preinstalled snaps.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
a37a0ce. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: FrederikBolding