Description of problem:
Can't create a content credential through the web ui.

Version-Release number of selected component (if applicable):
6.14.3

How reproducible:
Always

Steps to Reproduce:
1. Navigate to content credential creation menu.
2. In the Type dropdown, select SSL Certificate.
3. Paste cert into Content Credential Contents. This problem also exists for uploading the cert file.
4. Click save.

Actual results:
The save operation runs infinitely.

Expected results:
The content credential should save.

Additional info:
I'm using Google Chrome.
The same operation works with hammer:

[root@ip-172-31-24-152 ~]# hammer content-credential create \
> --content-type cert \
> --name "ip-172-31-16-56.us-west-1.compute.internal" \
> --organization "Acme Org" \
> --path /tmp/katello-server-ca.crt
Content Credential created.