prevent editing of displayName field

[areisle]

Describe the bug
when editing a source, user can edit the display name

To Reproduce
Steps to reproduce the behaviour:

1. go to any source record
2. click edit
3. type something in display name field

Expected behaviour
should be able to submit changes
should not be able to edit displayName field

Versions (please complete the following information):

• tested on develop (commit f6dd508) and master (93f30b9

Additional context
tested on prod and it doesn't seem to have this issue

[creisle]

ya, users aren't allowed to manually edit the displayName field. This field should just not allow changes in the first place

[areisle]

ah, so then this is actually more correct on dev than on master, but should still be changed to prevent users editing the field in the first place