scan_scmclients_for_path() now calls setup() on any SCMClients

scanned, tracking any dependencies that fail to be found. This ensures

that the clients are in a proper state and that we can provide useful

information if we fail to find a repository when there are dependency

errors present.
The code that invokes this for commands will output that list of failed

dependencies only if it can't find a match. Debug information continues

to show the dependency errors regardless.

Unit tests pass on Python 3.7-3.11.
Posted this change for review.
Tested posting a change in a non-repository with missing dependencies.

Saw the debug error log information and the visible error information

with the missing dependencies.