OZG-5899 implement code review comments

vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/files/FileITCase.java

@@ -127,9 +127,9 @@ class FileITCase {
 			void validateSecondAttachmentFileContent() {
 				callServiceGetAttachments();
 
-				var attachment1 = responseCaptor.getValue().getFile(1);
+				var attachment2 = responseCaptor.getValue().getFile(1);
 
-				assertThat(attachment1.getId()).isEqualTo(ID2.toString());
+				assertThat(attachment2.getId()).isEqualTo(ID2.toString());
 			}
 		}
 
@@ -146,6 +146,7 @@ class FileITCase {
 				callServiceGetAttachments();
 
 				verify(responseObserver).onNext(responseCaptor.capture());
+				assertThat(responseCaptor.getValue().getFileCount()).isEqualTo(2);
 			}
 		}
 
@@ -162,6 +163,7 @@ class FileITCase {
 				callServiceGetAttachments();
 
 				verify(responseObserver).onNext(responseCaptor.capture());
+				assertThat(responseCaptor.getValue().getFileCount()).isEqualTo(2);
 			}
 		}