fix: Remove Frame Processor when Camera unmounts (#1960)

* unsetFrameProcessor when camera view is removed

* Use `this.lastFrameProcessor` instead

---------

Co-authored-by: Marc Rousavy <marcrousavy@hotmail.com>

package/src/Camera.tsx

@@ -431,6 +431,13 @@ export class Camera extends React.PureComponent<CameraProps> {
       this.lastFrameProcessor = frameProcessor
     }
   }
+
+  /** @internal */
+  componentWillUnmount(): void {
+    if (this.lastFrameProcessor !== null) {
+      this.unsetFrameProcessor()
+    }
+  }
   //#endregion
 
   /** @internal */