fix PD StartTimeout if no CRD updated

[csuzhangxc]

What problem does this PR solve?

in #5071, a new startTimeout field for PD spec is introduced, and it's default value is set via CRD.

If a user upgrades the TiDB-Operator image before updating the CRD, this new field will become 0 and PD will be rolling restarted.

What is changed and how does it work?

Code changes

• Has Go code change
• Has CI related scripts change

Tests

• Unit test
• E2E test
• Manual test
  • ensure no rolling restart for PD after updated the image to this PD's version.
• No code

Side effects

• Breaking backward compatibility
• Other side effects:

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Release Notes

Please refer to Release Notes Language Style Guide before writing the release note.

[ti-chi-bot]

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[csuzhangxc]

/cherry-pick release-1.5

[ti-chi-bot]

@csuzhangxc: The label(s) /release-1.5 cannot be applied, because the repository doesn't have them.

In response to this:

/cherry-pick release-1.5

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

@csuzhangxc: new pull request created to branch release-1.5: #5097.

In response to this:

/cherry-pick release-1.5

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.