refactor(language-service): create getTypeDefinitionAtPosition stubs (#39050)

Create stubs for getTypeDefinitionAtPosition for both VE and Ivy Language Service implementations.
This will prevent failed requests when it is implemented on the vscode plugin side

PR Close #39050

packages/language-service/ivy/ts_plugin.ts

@@ -24,8 +24,13 @@ export function create(info: ts.server.PluginCreateInfo): ts.LanguageService {
     return diagnostics;
   }
 
+  function getTypeDefinitionAtPosition(fileName: string, position: number) {
+    return undefined;
+  }
+
   return {
     ...tsLS,
     getSemanticDiagnostics,
+    getTypeDefinitionAtPosition,
   };
 }

packages/language-service/src/ts_plugin.ts

@@ -110,16 +110,20 @@ export function create(info: tss.server.PluginCreateInfo): tss.LanguageService {
     return ngLS.getDefinitionAndBoundSpan(fileName, position);
   }
 
-  const proxy: tss.LanguageService = Object.assign(
+  function getTypeDefinitionAtPosition(fileName: string, position: number) {
+    // Not implemented in VE Language Service
+    return undefined;
+  }
+
+  return {
     // First clone the original TS language service
-      {}, tsLS,
+    ...tsLS,
     // Then override the methods supported by Angular language service
-      {
     getCompletionsAtPosition,
     getQuickInfoAtPosition,
     getSemanticDiagnostics,
     getDefinitionAtPosition,
     getDefinitionAndBoundSpan,
-      });
+    getTypeDefinitionAtPosition,
-  return proxy;
+  };
 }