Only show "set encrypted" if folder is empty and has no empty files/folder in it

Signed-off-by: tobiasKaminsky <tobias@kaminsky.me>

app/src/androidTest/java/com/owncloud/android/files/FileMenuFilterIT.kt

@@ -77,6 +77,7 @@ class FileMenuFilterIT : AbstractIT() {
         every { mockOperationsServiceBinder.isSynchronizing(any(), any()) } returns false
         every { mockComponentsGetter.operationsServiceBinder } returns mockOperationsServiceBinder
         every { mockStorageManager.getFileById(any()) } returns OCFile("/")
+        every { mockStorageManager.getFolderContent(any(), any()) } returns ArrayList<OCFile>()
     }
 
     @Test

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

@@ -594,7 +594,11 @@ public class FileMenuFilter {
         if (isSingleSelection()) {
             OCFile file = files.iterator().next();
 
-            return file.isFolder() && file.getFileLength() == EMPTY_FILE_LENGTH;
+            boolean noChildren = componentsGetter
+                .getStorageManager()
+                .getFolderContent(file, false).size() == EMPTY_FILE_LENGTH;
+
+            return file.isFolder() && file.getFileLength() == EMPTY_FILE_LENGTH && noChildren;
         } else {
             return false;
         }