remove incorrect call of removeObserver from RCTDeviceInfo

Summary:
changelog: [internal]


in recent commit, facebook@470bc40, use of KVO was removed. 
But `removeObserver` when `addObserver` was not called leads to a crash and must be removed as well.

Differential Revision: D69918158

packages/react-native/React/CoreModules/RCTDeviceInfo.mm

@@ -122,8 +122,6 @@ - (void)_cleanupObservers
 
   [[NSNotificationCenter defaultCenter] removeObserver:self name:RCTBridgeWillInvalidateModulesNotification object:nil];
 
-  [RCTKeyWindow() removeObserver:self forKeyPath:kFrameKeyPath];
-
 #if TARGET_OS_IOS
   [[NSNotificationCenter defaultCenter] removeObserver:self name:UIDeviceOrientationDidChangeNotification object:nil];
 #endif