refactor: replace golang.org/x/exp with stdlib

[Juneezee]

Proposed changes

These experimental packages are now available in the Go standard library.

1. golang.org/x/exp/slices -> slices (https://go.dev/doc/go1.21#slices)
2. golang.org/x/exp/maps -> maps (https://go.dev/doc/go1.21#maps)

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

[github-actions]

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[Juneezee]

I have hereby read the F5 CLA and agree to its terms

[javorszky]

Nice, thank you! Notably the signature for maps.Keys changed between the exp package and std library, which is why the slices.Collect is there.

Also checked the rest of the codebase, no other place uses exp/maps or exp/slices.

[Juneezee]

Rebased to fix conflicts.

[Juneezee]

@javorszky Thanks you reviewing and approving the PR 😊 ! Seems like the workflow needs your approval again to run

[javorszky]

@Juneezee it's running 2 more checks at the time of writing this comment. I expect both to finish, and the PR to be merged as soon as both return green.

Thanks for fixing these!

[javorszky]

it's running 2 more checks

only to open up another 16... 😆 Right, working on these