configs: Custom variable validation is no longer experimental

[apparentlymart]

All of the feedback from the experiment described enhancements that can potentially be added later without breaking changes, so this change simply removes the experiment gate from the feature as originally implemented with no changes to its functionality.

Further enhancements may follow in later releases, but the goal of this change is just to ship the feature exactly as it was under the experiment.

Most of the changes here are cleaning up the experiment opt-ins from our test cases. The most important parts are in configs/experiments.go and in experiments/experiment.go.

[codecov]

Codecov Report

Merging #25054 into master will decrease coverage by 0.01%.
The diff coverage is n/a.

Impacted Files	Coverage Δ
configs/experiments.go	77.27% <ø> (-2.73%)	⬇️
terraform/node_resource_plan.go	91.80% <0.00%> (-1.64%)	⬇️
backend/remote/backend_common.go	54.57% <0.00%> (-0.68%)	⬇️
states/statefile/version4.go	56.16% <0.00%> (-0.29%)	⬇️
terraform/evaluate.go	53.60% <0.00%> (+0.45%)	⬆️

[api-py]

I heard about this a bit late and would like to thank you for this enhancement on input validation of variables.

We do a lot of manipulation with locals and mesh together variables, data and other source of values.

Would it be possible to extend the validation block also for locals?

It would add a lot of value for enforcing rules in one place for us.

Many thanks,
Dejan

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

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