Optimize MetalRedrawer synchronization (#2673)

Remove `inflightSemaphore` because does not prevent from awaiting the
main thread on the `nextDrawable()`.
Replace `InflightCommandBuffers` and replace it with the Dispatch Group.

Fixes
https://youtrack.jetbrains.com/issue/CMP-9494/Optimize-MetalRedrawer-synchronization

## Release Notes
N/A

Author: ASalavei

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

@@ -439,9 +439,6 @@ internal class MetalRedrawer(
                     picture.close()
                     surface.flushAndSubmit()
 
-                    surface.close()
-                    renderTarget.close()
-
                     if (useSeparateRenderThreadWhenPossible) {
                         dispatch_semaphore_signal(drawCanvasSemaphore)
                     }
@@ -481,6 +478,9 @@ 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)