Bug with Media Gallery: cannot properly save file formats

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.0.1 CE GA2, Master
• Fix Version/s: 7.1.X, Master
• Component/s: DM, DM > Media Gallery
• Labels: None
• Story Points: 1
• Fix Priority: 4
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/41531

Steps to reproduce:

1. Add Media Gallery portlet to page
2. Go to Configuration > Setup > Display Settings
3. Select at least two media types under Show Media Type
4. Save configuration
5. Assert available media types are saved
6. Remove one media type from the available list
7. Save configuration
8. Assert media type is not removed
9. Remove at least two media types
10. Save configuration

Expected result: Media types are removed from the Available list
Actual result: Media types are still under Available and another media type is added. Please see attached video.

Reproduced on:
Tomcat 8.0.32 + MySQL 5.6
Portal master GIT ID: f40a2c2deae16efaf6084e9f157d6b3f97882932