fix: clear stack watchers map when lost leader lease

[emosbaugh]

Description

When the lease is lost the context is cancelled and the stack processing loop exits ("Stack done"). Once the lease is re-aquired the stacks never get created because the map to prevent them from getting added twice is not cleared.

https://github.com/k0sproject/k0s/pull/5123/files#diff-76a26da950291d89ea652adeec6f6108d7ef34165e027972910c934bbdcce264R206-R210

Fixes #5122

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

How Has This Been Tested?

• Manual test
• Auto test added

Checklist:

• My code follows the style guidelines of this project
• My commit messages are signed-off
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

[emosbaugh]

This is still a work in progress. I intend to add a test.

[emosbaugh]

This is still a work in progress. I intend to add a test.

I have added a test. The test takes about 5 seconds as im beholden to the debouncing of the stack applier.

[emosbaugh]

this was largely lifted from the ExtensionsController

[twz123]

Can you maybe check if that's fixed by #5062, too?

[emosbaugh]

Can you maybe check if that's fixed by #5062, too?

Yes. I will checkout your branch and run the tests from mine. They exhibit the issue prior to my change.

[emosbaugh]

Can you maybe check if that's fixed by #5062, too?

Yes. I will checkout your branch and run the tests from mine. They exhibit the issue prior to my change.

Your change also solves the issue. I've created a pull request into your branch with my test from this one. Feel free to close this pr.

twz123#134