Expose preferred locations config (#2762)

[ti-chi-bot]

This is an automated cherry-pick of #2762

What problem does this PR solve?

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Code changes

• Has exported function/method change
• Has exported variable/fields change
• Has interface methods change
• Has persistent data change

Side effects

• Possible performance regression
• Increased code complexity
• Breaking backward compatibility

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation
• Need to update the tidb-ansible repository
• Need to be included in the release note

[shiyuhang0]

/run-all-tests

[shiyuhang0]

/run-all-tests

[shiyuhang0]

/run-all-tests tidb=v7.3.0 tikv=v7.3.0 pd=v7.3.0

[shiyuhang0]

/run-all-tests tidb=v6.5.0 tikv=v6.5.0 pd=v6.5.0

[shiyuhang0]

/run-all-tests tidb=v6.1.0 tikv=v6.1.0

[shiyuhang0]

/run-all-tests tidb=release-6.5 tikv=release-6.5

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: shiyuhang0, zhangyangyu

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/pingcap/tispark/blob/master/OWNERS)~~ [shiyuhang0] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2023-10-10 03:14:52.645801574 +0000 UTC m=+1108490.232911719: :ballot_box_with_check: agreed by shiyuhang0.
• 2023-10-10 08:15:17.185559422 +0000 UTC m=+1126514.772669567: :ballot_box_with_check: agreed by zhangyangyu.