OZG-6620 Refactoring test name

alfa-client/libs/postfach/src/lib/postfach-mail-form/postfach-mail.formservice.spec.ts

@@ -88,7 +88,7 @@ describe('PostfachMailFormservice', () => {
     });
   });
 
-  describe('get signatur', () => {
+  describe('getSignatur', () => {
     const postfachSettings = createPostfachSettings();
 
     beforeEach(() => {