fix test

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Author: kinto0

src/test/mocks/extensions.ts

@@ -7,7 +7,7 @@ export class MockExtensions implements IExtensions {
     all: readonly Extension<unknown>[] = [];
     onDidChange: Event<void> = (() => {
         throw new Error('Method not implemented');
-    })();
+    });
     getExtension(extensionId: string): Extension<unknown> | undefined;
     getExtension<T>(extensionId: string): Extension<T> | undefined;
     getExtension(_extensionId: unknown): import('vscode').Extension<unknown> | undefined {