Replace opacity console error with warning

Summary: This error message is remarkably aggressive relative to the severity of the issue, particularly since the pattern in question is used / necessary throughout the codebase. Animated ReactART components with set opacities trigger this error, and opacity coming from the style prop is not respected.

Reviewed By: sahrens

Differential Revision: D3177554

fb-gh-sync-id: 96061d5ff526177814996b28e4394e6649839582
fbshipit-source-id: 96061d5ff526177814996b28e4394e6649839582

Libraries/Animated/src/AnimatedImplementation.js

@@ -1394,7 +1394,7 @@ function createAnimatedComponent(Component: any): any {
 
       for (var key in ViewStylePropTypes) {
         if (!Component.propTypes[key] && props[key] !== undefined) {
-          console.error(
+          console.warn(
             'You are setting the style `{ ' + key + ': ... }` as a prop. You ' +
             'should nest it in a style object. ' +
             'E.g. `{ style: { ' + key + ': ... } }`'