Missing TH on admin form tables

[rachidatecs]

Current Behavior

The custom tables we're using throughout DJA for contacts feature a 'copy email' column on the right. That column 's TDs do not have any associated TH.

Expected Behavior

Every TD should have an associated TH either in the THEAD or as the first table cell in its row.

Per this slack discussion, we should have a visible TH that says ‘Action’

This should be applied to every instance of DJA table that features a 'copy email' button.

Steps to Reproduce

1. Navigate to a domain request with other contacts or portfolio with members and admins.
2. Inspect table.

Environment

No response

Additional Context

No response

Issue Links

No response

[abroddrick]

Soft sprinting for 57, just because it's a nice easy ticket that shouldn't take a ton of time. Adding analyst experience, though it's mostly an accessibility thing.