[MNT] Changes to no soft dependency tests

[MatthewMiddlehurst]

What does this implement/fix? Explain your changes.

Merged the two soft dependency workflow jobs into a single one which runs all tests on the periodic workflow and all tests but the "TestAllEstimator" tests on PRs.

Slims down the module soft dependency check. This did not actually work previously as the module variable was an empty list. Previously the test would check for "soft dependency modules" which rely on soft dependencies, the new test removes this concept. Everything must be isolated with no exceptions (yet) in the new version. Skips modules containing "tests" in the path on PRs.

[aeon-actions-bot]

Thank you for contributing to aeon

I have added the following labels to this PR based on the title: [ $\color{#EC843A}{\textsf{maintenance}}$ ].

The Checks tab will show the status of our automated tests. You can click on individual test runs in the tab or "Details" in the panel below to see more information if there is a failure.

If our pre-commit code quality check fails, any trivial fixes will automatically be pushed to your PR unless it is a draft.

Don't hesitate to ask questions on the aeon Slack channel if you have any.

[TonyBagnall]

looks fine to me, maybe @chrisholder could take a look?