ios: handle resetting color

Author: xindixu

ios/EnrichedMarkdown.mm

@@ -901,6 +901,8 @@ - (void)applySelectionColor:(const EnrichedMarkdownProps &)props toTextView:(ENR
 #if !TARGET_OS_OSX
   if (isColorMeaningful(props.selectionColor)) {
     ENRMSetSelectionColor(textView, RCTUIColorFromSharedColor(props.selectionColor));
+  } else {
+    ENRMSetSelectionColor(textView, nil); // resets to inherited / system tint
   }
 #endif
 }

ios/EnrichedMarkdownText.mm

@@ -416,6 +416,8 @@ - (void)updateProps:(Props::Shared const &)props oldProps:(Props::Shared const &
 #if !TARGET_OS_OSX
     if (isColorMeaningful(newViewProps.selectionColor)) {
       ENRMSetSelectionColor(_textView, RCTUIColorFromSharedColor(newViewProps.selectionColor));
+    } else {
+      ENRMSetSelectionColor(_textView, nil); // resets to inherited / system tint
     }
 #endif
   }

ios/input/EnrichedMarkdownTextInput.mm

@@ -292,6 +292,8 @@ - (void)updateProps:(Props::Shared const &)props oldProps:(Props::Shared const &
   if (newViewProps.selectionColor != oldViewProps.selectionColor) {
     if (isColorMeaningful(newViewProps.selectionColor)) {
       ENRMSetSelectionColor(_textView, RCTUIColorFromSharedColor(newViewProps.selectionColor));
+    } else {
+      ENRMSetSelectionColor(_textView, nil); // resets to inherited / system tint
     }
   }