mobile: turning up release validation CI

[alyssawilk]

copied from the mobile repo, and edited to run for repo merge. Only runs for mobile PRs.

Risk Level: low
Testing: first push shows it worked successfully
Docs Changes: n/a
Release Notes: n/a
part of #23758

[repokitteh-read-only]

As a reminder, PRs marked as draft will not be automatically assigned reviewers,
or be handled by maintainer-oncall triage.

Please mark your PR as ready when you want it to be reviewed!

🐱

Caused by: #24171 was opened by alyssawilk.

see: more, trace.

[phlax]

please dont do this - rather clean up the yaml

this is unnecessary

[alyssawilk]

it's not necessary but it makes it a lot less annoying to change workflow files as it means git add * will add them.

[phlax]

looks good, altho im a little concerned that we are adding a lot of CI that will still run when not strictly required

the paths (and paths-ignore) pattern for workflow triggers is cool - i checked re azp to do the same thing - it seems we can altho i think we probably still need to use the pattern we have discussed as it is more about not/triggering steps within a workflow there

i was a little bit confused by the .gitignore change - mostly because i could see that the yaml should not pass linting so assumed that it was to prevent linting

i realise now that it does the opposite - ie ensure those files are included - but its not necessary as there is already:

 15 !\.github

checking this confirms

$ touch .github/workflows/asdf
$ git status .github/workflows/
On branch tooling-yamllint2
Untracked files:
  (use "git add <file>..." to include in what will be committed)
	.github/workflows/asdf

re linting the reason these files were not picked up is due to it only searching for .yaml files and not .yml - im fixing that now (envoyproxy/toolshed#623)

and will lint the existing files as that lands

[phlax]

yaml lint/cleanup pr is #24197