tasks: Test cross-project PR test request

[martinpitt]

This covers the regression with job-runner for cross-project test requests: https://github.com/cockpit-project/bots/pull/6045

Due to that revert, this currently tests the old tests-invoke code path. Allow some flexibility in the status description as tests-invoke and job-runner's descriptions are slightly different.

---

• [x] Builds on top of #592
• [x] Requires https://github.com/cockpit-project/bots/pull/6061

[martinpitt]

I created a https://github.com/cockpit-project/bots/tree/cross-job-runner branch which reverts https://github.com/cockpit-project/bots/pull/6045 . You can run it with

COCKPIT_BOTS_BRANCH=cross-job-runner tasks/run-local.sh

This fails with trying to post statuses to cockpituous, as the mock doesn't allow that:

Traceback (most recent call last):
  File "/work/bots/lib/aio/job.py", line 166, in run_job
    await status.post('pending', 'In progress')
  File "/work/bots/lib/aio/github.py", line 181, in post
    await self.api.post(self.resource, {
  File "/work/bots/lib/aio/github.py", line 70, in post
    return await post_once()
           ^^^^^^^^^^^^^^^^^
  File "/work/bots/lib/aio/github.py", line 64, in post_once
    async with self.session.post(self.api / resource, json=body) as response:
  File "/usr/lib64/python3.12/site-packages/aiohttp/client.py", line 1194, in __aenter__
    self._resp = await self._coro
                 ^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.12/site-packages/aiohttp/client.py", line 693, in _request
    resp.raise_for_status()
  File "/usr/lib64/python3.12/site-packages/aiohttp/client_reqrep.py", line 1060, in raise_for_status
    raise ClientResponseError(
aiohttp.client_exceptions.ClientResponseError: 405, message='Method not allowed: /repos/cockpit-project/cockpituous/statuses/cef660f099a496a2e0e9ad1ebd5ac076562778f4', url=URL('http://127.0.0.7:8443/repos/cockpit-project/cockpituous/statuses/cef660f099a496a2e0e9ad1ebd5ac076562778f4')

it would also fail later on in the POST messages assertions.