OZG-5286 add test for muk handling

enterprise-adapter/src/test/java/de/ozgcloud/eingang/enterprise/entry/EnterpriseEntryITCase.java

@@ -77,6 +77,13 @@ class EnterpriseEntryITCase {
 			assertThat(formData.getFormData()).containsKeys("Haushaltsjahr", "Anlage_1", "Anlage_2");
 		}
 
+		@Test
+		void shouldHaveMukServiceKonto() {
+			var formData = doPostRequest();
+
+			assertThat(formData.getHeader().getServiceKonto().getType()).isEqualTo("MUK");
+		}
+
 		@SneakyThrows
 		private FormData doPostRequest() {
 			mockMvc.perform(multipart("/antrag")