Remove GetInstanceIfCreated and use Instance everywhere

Remove the defensive null checks in bridge processing. If bridge processing
is being called, the instance must already exist since objects need to be
registered for bridge processing to happen.

Co-authored-by: simonrozsival <374616+simonrozsival@users.noreply.github.com>

Author: Copilot

src/Mono.Android/Microsoft.Android.Runtime/ManagedValueManager.cs

@@ -32,8 +32,6 @@ class ManagedValueManager : JniRuntime.JniValueManager
 	static Lazy<ManagedValueManager> s_instance = new (() => new ManagedValueManager ());
 
 	public static ManagedValueManager Instance => s_instance.Value;
-	
-	static ManagedValueManager? GetInstanceIfCreated () => s_instance.IsValueCreated ? s_instance.Value : null;
 
 	unsafe ManagedValueManager ()
 	{
@@ -444,24 +442,13 @@ static unsafe void BridgeProcessingFinished (MarkCrossReferencesArgs* mcr)
 
 		// Schedule cleanup of _registeredInstances on a thread pool thread.
 		// The bridge thread must not take lock(_registeredInstances) — see deadlock notes.
-		// Only schedule if instance exists (bridge processing typically implies registered objects exist).
-		var instance = GetInstanceIfCreated ();
-		if (instance != null) {
-			Task.Run (instance.CollectPeers);
-		}
+		Task.Run (Instance.CollectPeers);
 	}
 
 	static unsafe ReadOnlySpan<GCHandle> ProcessCollectedContexts (MarkCrossReferencesArgs* mcr)
 	{
 		List<GCHandle> handlesToFree = [];
-		
-		// Bridge processing typically implies registered objects exist, but check defensively
-		// to avoid creating the ManagedValueManager instance unnecessarily.
-		ManagedValueManager? instance = GetInstanceIfCreated ();
-		if (instance == null) {
-			// No registered objects, nothing to process
-			return ReadOnlySpan<GCHandle>.Empty;
-		}
+		ManagedValueManager instance = Instance;
 
 		for (int i = 0; (nuint)i < mcr->ComponentCount; i++) {
 			StronglyConnectedComponent component = mcr->Components [i];