Fix race conditions in MetalRedrawer (#2672)

Await when all scheduled tasks in async rendering queue are completed
before clearing resources.
Move surface and renderTarget closing to the critical section.

Fixes:
https://youtrack.jetbrains.com/issue/CMP-8144/Crash-when-enabling-parallel-rendering-in-MetalRedrawer-for-iOS
Fixes:
https://youtrack.jetbrains.com/issue/CMP-7598/Skia-crash-on-iOS-GrResourceCachenotifyARefCntReachedZero

## Release Notes
### Fixes - iOS
- Fix the crash that may occur when the Compose container disposes.

Author: ASalavei

compose/ui/ui/src/iosMain/kotlin/androidx/compose/ui/window/MetalRedrawer.ios.kt

@@ -278,6 +278,14 @@ internal class MetalRedrawer(
         caDisplayLink?.invalidate()
         caDisplayLink = null
 
+        // Wait until all scheduled rendering tasks are completed to eliminate race conditions
+        // when clearing the resources
+        if (useSeparateRenderThreadWhenPossible) {
+            trace("MetalRedrawer:dispose:waitForAsyncRenderingTasks") {
+                dispatch_sync(renderingDispatchQueue) {}
+            }
+        }
+
         pictureRecorder.close()
         context.close()
     }
@@ -431,6 +439,9 @@ internal class MetalRedrawer(
                     picture.close()
                     surface.flushAndSubmit()
 
+                    surface.close()
+                    renderTarget.close()
+
                     if (useSeparateRenderThreadWhenPossible) {
                         dispatch_semaphore_signal(drawCanvasSemaphore)
                     }
@@ -470,9 +481,6 @@ internal class MetalRedrawer(
                         }
                     }
 
-                    surface.close()
-                    renderTarget.close()
-
                     // Track current inflight command buffers to synchronously wait for their schedule in case app goes background
                     inflightCommandBuffers.add(commandBuffer)