Ensure jobs are created if task is in waiting state

[wxtim]

Closes #6172

Check List

• [x] I have read CONTRIBUTING.md and added my name as a Code Contributor.
• [x] Contains logically grouped changes (else tidy your branch by rebase).
• [x] Does not contain off-topic changes (use other PRs for other changes).
• [x] Applied any dependency changes to both setup.cfg (and conda-environment.yml if present).
• [x] Tests are included (or explain why tests are not needed).
• [x] CHANGES.md entry included if this is a change that can affect users
• [x] Cylc-Doc pull request opened if required at cylc/cylc-doc/pull/XXXX.
• [x] If this is a bug fix, PR should be raised against the relevant ?.?.x branch.

[wxtim]

@oliver-sanders I may need some assistance working out why this change has caused very small changes in a couple of TUI tests::

[oliver-sanders]

Tui is just showing you what the data store contains (i.e. these Tui test failures are nothing to do with Tui).

[oliver-sanders]

(rebase to pick up flake8 fixes on upstream/8.3.x)