Attempt to fix test on CI.

The test is failing on CI with this error:
expected instance of: io.element.android.libraries.architecture.Async$Success
but was instance of : io.element.android.libraries.architecture.Async$Loading
with value          : Loading(prevData=null)

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/encryption/FakeEncryptionService.kt

@@ -72,7 +72,7 @@ class FakeEncryptionService : EncryptionService {
         this.isLastDevice = isLastDevice
     }
 
-    override suspend fun isLastDevice(): Result<Boolean> {
+    override suspend fun isLastDevice(): Result<Boolean> = simulateLongTask {
         return Result.success(isLastDevice)
     }