[CSSMatchedStyles] Do not bail out when getAnimatedStylesForNode errors

Previously, we were returning `null` for `CSSMatchedStyles` creation
when either `getMatchedStylesForNode` or `getAnimatedStylesForNode`
errored.

However, native UI DevTools do not implement `getAnimatedStylesForNode`
CDP method; thus it causes `CSSMatchedStyles` to be not created
since this method now errors.

I have updated the logic to not bail out from `matchedStyles`
creation for animated styles so that UI native DevTools still works.

This also makes sense for the case where somehow
`getAnimatedStylesForNode` returns an error (then we don't show the
animated styles until it stops erroring after computed style updates)

Fixed: 395131432
Change-Id: Ic12568467d0cd34ee95a836b94f52a1182945b8b
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6243807
Commit-Queue: Philip Pfaffe <[email protected]>
Auto-Submit: Ergün Erdoğmuş <[email protected]>
Reviewed-by: Philip Pfaffe <[email protected]>

Author: ergunsh

front_end/core/sdk/CSSModel.ts

@@ -362,7 +362,7 @@ export class CSSModel extends SDKModel<EventTypes> {
       shouldGetAnimatedStyles ? this.agent.invoke_getAnimatedStylesForNode({nodeId}) : undefined,
     ]);
 
-    if (matchedStylesResponse.getError() || animatedStylesResponse?.getError()) {
+    if (matchedStylesResponse.getError()) {
       return null;
     }