Summary:
yamllint wasn't being run by arc since the arg was the last thing passed
to the script. This fixes the lint run, parsing.
There are too many errors to fix in one go, so I'll take a few passes at them
and leave the rest for folks to fix as they go.

Test Plan: Run `arc lint --trace` with a yaml file that shouldn't pass lint.

Reviewers: michelle, zasgar

Reviewed By: michelle
Signed-off-by: Vihang Mehta <vihang@pixielabs.ai>

Differential Revision: https://phab.corp.pixielabs.ai/D10057

GitOrigin-RevId: 268f6b83b0e4bcb3b9aa08cef11b7ffdf51145c3