Add validation for beta features in v1 remote Tasks/Pipelines

[lbernick]

Currently, when a user creates a v1 Task or Pipeline using beta features on their cluster, we validate that "enable-api-fields" is set to "alpha" or "beta", and if not, reject the Task or Pipeline.

However, no such validation is done for v1 remote Tasks or Pipelines. This is because we validate remote Task and Pipeline specs in the reconciler after converting them to v1beta1. This commit adds the same validation to remote v1 Tasks and Pipelines that we are already performing for local v1 Tasks and Pipelines.

/kind bug
Partially addresses #6616

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• n/a Has Docs if any changes are user facing, including updates to minimum requirements e.g. Kubernetes version bumps
• Has Tests included if any functionality added or changed
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Release Notes

Bug fix: Apply validation for beta features for v1 remote pipelines and tasks in the same way as already exists for pipelines and tasks created directly on cluster

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/reconciler/pipelinerun/resources/pipelineref.go	92.0%	92.3%	0.3
pkg/reconciler/taskrun/resources/taskref.go	88.9%	89.2%	0.3

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage-df to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/reconciler/pipelinerun/resources/pipelineref.go	92.0%	92.3%	0.3
pkg/reconciler/taskrun/resources/taskref.go	88.9%	89.2%	0.3

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage-df to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/reconciler/pipelinerun/resources/pipelineref.go	92.0%	92.3%	0.3
pkg/reconciler/taskrun/resources/taskref.go	88.9%	89.2%	0.3

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dibyom, vdemeester

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[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/reconciler/pipelinerun/resources/pipelineref.go	92.0%	92.3%	0.3
pkg/reconciler/taskrun/resources/taskref.go	88.9%	89.2%	0.3

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage-df to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/reconciler/pipelinerun/resources/pipelineref.go	92.0%	92.3%	0.3
pkg/reconciler/taskrun/resources/taskref.go	88.9%	89.2%	0.3

[Yongxuanzhang]

/lgtm