test: fix syntax error for slide-toggle mdc test

Fixes a syntax error for the slide-toggle MDC spec file.
The syntax error most likely has been introduced through
the cherry-pick of the commit initially targeting master.

Author: devversion

src/material-experimental/mdc-slide-toggle/slide-toggle.spec.ts

@@ -773,7 +773,7 @@ describe('MDC-based MatSlideToggle with forms', () => {
       fixture.detectChanges();
 
       expect(testComponent.isSubmitted).toBe(true);
-    })));
+    }));
 
     it('should have proper invalid state if unchecked', fakeAsync(() => {
       testComponent.isRequired = true;