fix: ensure global podTemplate configuration is merged correctly

[l-qing]

fix #7551

Adjust the behavior of how global Pod templates are merged with TaskRun or PipelineRun.
The env and volumes fields are merged by the name value in the array elements.

Changes

Submitter Checklist

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

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Release Notes

Merge the `env` and `volumes` from the podTemplate in the pipelineRun or TaskRun with the global defaults, instead of only considering the specified in the Run's.

/kind bug

[tekton-robot]

Hi @l-qing. Thanks for your PR.

I'm waiting for a tektoncd member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[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/apis/pipeline/pod/template.go	Do not exist	75.3%

[vdemeester]

/ok-to-test
/cc @piyush-garg

[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/apis/pipeline/pod/template.go	Do not exist	75.3%

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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

The full list of commands accepted by this bot can be found here.

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Needs approval from an approver in each of these files:

• OWNERS [JeromeJu,vdemeester]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[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/apis/pipeline/pod/template.go	Do not exist	75.3%

[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/apis/pipeline/pod/template.go	Do not exist	75.3%

[chitrangpatel]

/lgtm