Revert "[RN][iOS] Make universal builds"

This reverts commit b96ca538e4. While iPad
support is nice to have, we are not ready for a publish in App Store.
During the upload to iTunes Connect, a verification of the .ipa fails
because:

- app icons for iPad are missing:
  - 76x76 pixels in .png format for iOS versions >= 7.0,
  - 167x167 pixels in .png format for iOS versions supporting iPad Pro,
  - 152x152 pixels in .png format for iOS versions >= 7.0,
- orientations required for iPad Mutitasking are missing:
  - UIInterfaceOrientationPortraitUpsideDown.

ios/jitsi-meet-react.xcodeproj/project.pbxproj

@@ -969,7 +969,6 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = org.jitsi.JitsiMeet.ios;
 				PRODUCT_NAME = "jitsi-meet-react";
-				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
 		};
@@ -1006,7 +1005,6 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = org.jitsi.JitsiMeet.ios;
 				PRODUCT_NAME = "jitsi-meet-react";
-				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;
 		};