feat(language-service): completions for output $event properties in (#34570)

This commit adds support for completions of properties on `$event`
variables in bound outputs.

This is the second major PR to support completions for `$event`
variables (https://github.com/angular/vscode-ng-language-service/issues/531).
The final completion support that must be provided is for `$event`
variables in bindings targeting DOM events, like `(click)`.

PR Close #34570

packages/language-service/src/completions.ts

@@ -316,7 +316,6 @@ function attributeValueCompletions(info: AstResult, htmlPath: HtmlAstPath): ng.C
     templatePath.tail.visit(visitor, null);
     return visitor.results;
   }
-
   // In order to provide accurate attribute value completion, we need to know
   // what the LHS is, and construct the proper AST if it is missing.
   const htmlAttr = htmlPath.tail as Attribute;