fix(language-service): Make metadata in Declaration non-optional (#34936)

The `metadata` field in `Declaration` should not be optional.

PR Close #34936

packages/language-service/src/diagnostics.ts

@@ -96,9 +96,6 @@ export function getDeclarationDiagnostics(
         span: error.span,
       });
     }
-    if (!metadata) {
-      continue;  // declaration is not an Angular directive
-    }
     if (metadata.isComponent) {
       if (!modules.ngModuleByPipeOrDirective.has(declaration.type)) {
         results.push({

packages/language-service/src/types.ts

@@ -124,7 +124,7 @@ export interface Declaration {
   /**
    * Reference to the compiler directive metadata for the declaration.
    */
-  readonly metadata?: CompileDirectiveMetadata;
+  readonly metadata: CompileDirectiveMetadata;
 
   /**
    * Error reported trying to get the metadata.