fix(ios): NSInternalInconsistencyException crash (#564)

Added additional checks to scroll without animation if already an animation is in progress to fix `NSInternalInconsistencyException` crash in iOS

Author: hrupesh

ios/ReactNativePageView.m

@@ -264,7 +264,7 @@ - (void)goTo:(NSInteger)index animated:(BOOL)animated {
             if (i == _currentIndex) {
                 continue;
             }
-            [self goToViewController:i direction:direction animated:animated shouldCallOnPageSelected: i == index];
+            [self goToViewController:i direction:direction animated:(!self.animating && i == index) shouldCallOnPageSelected: i == index];
         }
     }
 
@@ -274,12 +274,12 @@ - (void)goTo:(NSInteger)index animated:(BOOL)animated {
             if (i == _currentIndex || i >= numberOfPages) {
                 continue;
             }
-            [self goToViewController:i direction:direction animated:animated shouldCallOnPageSelected: i == index];
+            [self goToViewController:i direction:direction animated:(!self.animating && i == index) shouldCallOnPageSelected: i == index];
         }
     }
 
     if (diff == 0) {
-        [self goToViewController:index direction:direction animated:animated shouldCallOnPageSelected:YES];
+        [self goToViewController:index direction:direction animated:NO shouldCallOnPageSelected:YES];
     }
 }