Fixed text background color

Summary:
@public

This fixes an issue with the containerBackgroundColor property of `<Text>` nodes, where containerBackgroundColor was being overridden by the backgroundColor. I also fixed up the example so that it demonstrates the feature more clearly.

Test Plan:
* Check UIExplorer text example
* Run Catalyst snapshot tests and check MAdMan, Groups

Libraries/Text/RCTShadowText.m

@@ -125,13 +125,13 @@ static css_dim_t RCTMeasure(void *context, float width)
   }
 
   if (_color) {
-    [self _addAttribute:NSForegroundColorAttributeName withValue:self.color toAttributedString:attributedString];
+    [self _addAttribute:NSForegroundColorAttributeName withValue:_color toAttributedString:attributedString];
   }
   if (_isHighlighted) {
     [self _addAttribute:RCTIsHighlightedAttributeName withValue:@YES toAttributedString:attributedString];
   }
   if (_textBackgroundColor) {
-    [self _addAttribute:NSBackgroundColorAttributeName withValue:self.textBackgroundColor toAttributedString:attributedString];
+    [self _addAttribute:NSBackgroundColorAttributeName withValue:_textBackgroundColor toAttributedString:attributedString];
   }
 
   UIFont *font = [RCTConvert UIFont:nil withFamily:fontFamily size:fontSize weight:fontWeight style:fontStyle];

Libraries/Text/RCTText.m

@@ -32,6 +32,15 @@
   return self;
 }
 
+- (void)reactSetFrame:(CGRect)frame
+{
+  // Text looks super weird if its frame is animated.
+  // This disables the frame animation, without affecting opacity, etc.
+  [UIView performWithoutAnimation:^{
+    [super reactSetFrame:frame];
+  }];
+}
+
 - (void)setTextStorage:(NSTextStorage *)textStorage
 {
   _textStorage = textStorage;

Libraries/Text/RCTTextManager.m

@@ -34,6 +34,7 @@ RCT_EXPORT_MODULE()
 
 #pragma mark - View properties
 
+RCT_IGNORE_VIEW_PROPERTY(backgroundColor);
 RCT_REMAP_VIEW_PROPERTY(containerBackgroundColor, backgroundColor, UIColor)
 
 #pragma mark - Shadow properties