fix(safe): tx service url missing /api path

The Filecoin documentation doesn't exactly specifiy the full path to be
used with the SafeAPIKit SDK. After some digging I found that the API
isn't expected to be under /api by default. That means it needs to be
specified explicitly.

https://docs.safe.global/sdk/api-kit/guides/migrate-to-v2

Author: pheuberger

src/lib/safe/SafeApiKitStrategy.ts

@@ -8,7 +8,7 @@ export class FilecoinMainnetStrategy implements SafeApiKitStrategy {
   createInstance(): SafeApiKit.default {
     return new SafeApiKit.default({
       chainId: BigInt(314),
-      txServiceUrl: "https://transaction.safe.filecoin.io/",
+      txServiceUrl: "https://transaction.safe.filecoin.io/api",
     });
   }
 }
@@ -17,7 +17,7 @@ export class FilecoinTestnetStrategy implements SafeApiKitStrategy {
   createInstance(): SafeApiKit.default {
     return new SafeApiKit.default({
       chainId: BigInt(314159),
-      txServiceUrl: "https://transaction-testnet.safe.filecoin.io/",
+      txServiceUrl: "https://transaction-testnet.safe.filecoin.io/api",
     });
   }
 }