[AICodeCompletion] Fix Enter keypress behavior to be similar to Tab

This CL also fixes a bug which appears while editing value field and
getting a suggestion because of which the user had to press Tab/Enter
one additional time.

Bug: 502459959
Change-Id: I3ac81aa8fb62c4f6569828ab14ef9eb4247a794e
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/7806813
Commit-Queue: Jack Franklin <jacktfranklin@chromium.org>
Reviewed-by: Jack Franklin <jacktfranklin@chromium.org>
Auto-Submit: Samiya Caur <samiyac@chromium.org>

Author: samiyac

front_end/panels/elements/StylePropertiesSection.ts

@@ -907,8 +907,7 @@ export class StylePropertiesSection {
       return;
     }
     const sourceTreeElement = this.closestPropertyForEditing(this.#activeAiSuggestion.cssProperty.index);
-    if (!(sourceTreeElement instanceof StylePropertyTreeElement) ||
-        sourceTreeElement.property !== this.#activeAiSuggestion.cssProperty) {
+    if (!(sourceTreeElement instanceof StylePropertyTreeElement)) {
       return;
     }
     return sourceTreeElement;

front_end/panels/elements/StylesSidebarPane.ts

@@ -1918,14 +1918,18 @@ export class CSSPropertyPrompt extends UI.TextPrompt.TextPrompt {
           return;
         }
         break;
-      case 'Enter':
+      case 'Enter': {
         if (keyboardEvent.shiftKey) {
           return;
         }
         // Accept any available autocompletions and advance to the next field.
-        this.tabKeyPressed();
+        const handled = this.tabKeyPressed();
+        if (this.aiCodeCompletionProvider && handled) {
+          event.consume(true);
+        }
         keyboardEvent.preventDefault();
         return;
+      }
       case 'Escape':
         if (this.#handleEscape(keyboardEvent)) {
           return;