Synchronous rendering on Metal when annotation views are visible

[stefankarschti]

Implement conditional synchronous rendering on Metal backend when annotation views are visible, that is waiting for frames to fully complete by invoking [commandBuffer waitUntilCompleted]; in the swap method of the MLNMapViewMetalRenderableResource.

This is needed because the map transformation is set as soon as the camera is mutated, and annotations are positioned on the screen according to that in MLNMapView::renderSync -> updateAnnotationViews, while the frame rendering is completing asynchronously on Metal - which causes desynchronization.

ref: #2082
Fixes #2053

[github-actions]

Bloaty Results (iOS) 🐋

Compared to main

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +0.0%    +496  [ = ]       0    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results-ios/pr-2334-compared-to-main.txt

[michaelkirk]

Thank you so much, it looks much better now! ❤️