Copying resource tags in fusion

**Motivation**
I'd like to be able to copy a tag tied to a revision from a resource in fusion.

**Implementation notes**
- Could be through the three-dots that currently have some copying options.
- Could be a bit more indirect (and perhaps another feature entirely) which is to pre-fill the tag with the existing tag value if someone is trying to tag a resource at a revision that is already tagged.

In any case, provide a way to easily select the tag value, which isn't the case right now

Start at Fusion's resource revision tagging view and inspect the three-dots copy menu shown in the issue screenshot. Trace how an existing tag is displayed when tagging a revision, then determine which approach fits the current UI. Done means a user can easily select or reuse the tag value for a revision that is already tagged.

Written by the indexing model from the issue text.