fix: Don't start zoom animation if we are already on that exact zoom value (#3988)

* fix: Don't start zoom animation if we are already on that exact `zoom` value

* fix: Observe zoom ramp old and new values

Author: mrousavy

packages/react-native-vision-camera/ios/Hybrid Objects/HybridCameraController.swift

@@ -321,9 +321,16 @@ final class HybridCameraController: HybridCameraControllerSpec, NativeCameraCont
 
   func startZoomAnimation(zoom: Double, rate: Double) -> Promise<Void> {
     return captureDevice.withLock(queue) { completion in
+      if self.captureDevice.videoZoomFactor == zoom {
+        // We are already exactly on our target value
+        completion()
+        return
+      }
+
       var observation: NSKeyValueObservation?
       observation = self.captureDevice.observe(
         \.isRampingVideoZoom,
+        options: [.old, .new],
         changeHandler: { _, change in
           if change.oldValue == true && change.newValue == false {
             completion()