OZG-6710 [test] refactor test factory

src/test/java/de/ozgcloud/processor/vorgang/AttachmentTestFactory.java

 package de.ozgcloud.processor.vorgang;
 
-import de.ozgcloud.apilib.vorgang.grpc.OzgCloudFileGroupTestFactory;
+import de.ozgcloud.processor.vorgang.FileGroup.FileGroupBuilder;
 
 public class AttachmentTestFactory {
 
-	public static FileGroup createFileGroup() {
+	public static final String GROUP_NAME = "File Group Name";
+
+	public static FileGroup create() {
+		return createBuilder().build();
+	}
+
+	public static FileGroupBuilder createBuilder() {
 		return FileGroup.builder()
-				.name(OzgCloudFileGroupTestFactory.NAME)
-				.file(FileMetaDataTestFactory.create())
-				.build();
+				.name(GROUP_NAME)
+				.file(FileMetaDataTestFactory.create());
 	}
+
 }

src/test/java/de/ozgcloud/processor/vorgang/EingangTestFactory.java

@@ -13,7 +13,7 @@ public class EingangTestFactory {
 	public static Eingang.EingangBuilder createBuilder() {
 		return Eingang.builder()
 				.antragsteller(AntragstellerTestFactory.create())
-				.attachment(AttachmentTestFactory.createFileGroup())
+				.attachment(AttachmentTestFactory.create())
 				.formData(List.<FormDataEntry>of(
 						FormField.builder().name(FIELD_NAME).label(FIELD_LABEL).value(FIELD_VALUE).build(),
 						SubForm.builder().name(SUB_FORM_NAME).label(SUB_FORM_LABEL)