Don't restart the sync service if the client is shutting down (#7472)

* Don't restart the sync service if the client is shutting down

This was causing issues when clearing the cache:

1. The client would ask the SDK to clear the caches.
2. The SDK would stop the sync service, clear the caches and set the `pos` value of sliding sync to 0 so the HS returns all the required state the next time the client is used.
3. However, between the sync service being stopped with the `pos=0` change and the client being destroyed, there was enough time for the `SyncOrchestrator` to decide the sync service was stopped for no good reason since there is network connectivity and the app is on foreground, so it restarted the sync, with `pos=0`.
4. This value was persisted, and the next time the new client did an 'initial sync' it had a `pos != 0`, which the HS uses to avoid returning some required state it already fetched.
5. The room list now lacks state events for lots of rooms and room names, avatars, members, etc. are now missing.

---------

Co-authored-by: Benoit Marty <benoitm@element.io>

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/RustMatrixClient.kt

@@ -135,6 +135,7 @@ import org.matrix.rustcomponents.sdk.use
 import timber.log.Timber
 import java.io.File
 import java.util.Optional
+import java.util.concurrent.atomic.AtomicBoolean
 import kotlin.jvm.optionals.getOrNull
 import kotlin.time.Duration
 import kotlin.time.Duration.Companion.seconds
@@ -304,6 +305,10 @@ class RustMatrixClient(
         .buffer(Channel.UNLIMITED)
         .stateIn(sessionCoroutineScope, started = SharingStarted.Eagerly, initialValue = persistentListOf())
 
+    private val _isShuttingDown = AtomicBoolean(false)
+    override val isShuttingDown: Boolean
+        get() = _isShuttingDown.get()
+
     init {
         // Make sure the session delegate has a reference to the client to be able to logout on auth error
         sessionDelegate.bindClient(this)
@@ -666,11 +671,13 @@ class RustMatrixClient(
     }
 
     override suspend fun clearCache() {
+        _isShuttingDown.set(true)
         innerClient.clearCaches(innerSyncService)
         destroy()
     }
 
     override suspend fun logout(userInitiated: Boolean, ignoreSdkError: Boolean) {
+        _isShuttingDown.set(true)
         sessionCoroutineScope.cancel()
         // Remove current delegate so we don't receive an auth error
         clientDelegateTaskHandle?.cancelAndDestroy()
@@ -708,6 +715,8 @@ class RustMatrixClient(
     }
 
     override suspend fun deactivateAccount(password: String, eraseData: Boolean): Result<Unit> = withContext(sessionDispatcher) {
+        _isShuttingDown.set(true)
+
         Timber.w("Deactivating account")
         // Remove current delegate so we don't receive an auth error
         clientDelegateTaskHandle?.cancelAndDestroy()