fix spotbugs

Signed-off-by: alperozturk96 <alper_ozturk@proton.me>

Author: alperozturk96

app/src/main/java/com/owncloud/android/files/FileMenuFilter.java

@@ -314,9 +314,15 @@ private void filterEdit(
      */
     @NextcloudServer(max = 18)
     private boolean isRichDocumentEditingSupported(OCCapability capability, String mimeType) {
+        final var mimeTypeList = capability.getRichDocumentsMimeTypeList();
+        final var isMimeTypeListContainsMimeType = (mimeTypeList != null && mimeTypeList.contains(mimeType));
+
+        final var optionalMimeTypeList = capability.getRichDocumentsOptionalMimeTypeList();
+        final var isOptionalMimeTypeListContainsMimeType = (optionalMimeTypeList != null &&
+            optionalMimeTypeList.contains(mimeType));
+
         return isSingleFile() &&
-            (capability.getRichDocumentsMimeTypeList().contains(mimeType) ||
-                capability.getRichDocumentsOptionalMimeTypeList().contains(mimeType)) &&
+            (isMimeTypeListContainsMimeType || isOptionalMimeTypeListContainsMimeType) &&
             capability.getRichDocumentsDirectEditing().isTrue();
     }