Renaming an area does not allow you to create another area with the same name

[julianlam]

Steps to reproduce:

1. Create an area abc
2. Rename it to def
3. Attempt to create a new area abc

Received error:

Unexpected error: E11000 duplicate key error collection: prod-openbeta.areas index: metadata.area_id_1 dup key: { metadata.area_id: UUID("6a4f8206-cea5-54a8-b5c3-a833520577c5") }

[julianlam]

Note: Editing an area to a once-used name seems to be fine.

[CocoisBuggy]

I think this may be linked to #409 It's a holdover from when we were frequently seeding data and didn't have many edit features for the actual data

[CocoisBuggy]

should be resolved by #410