*: support rollback from higher version to 6.5

[wjhuang2016]

What problem does this PR solve?

Issue Number: close #45570

Problem Summary:
We checked DDLTableVersion == 2 in 6.5, but it may be set to a higher value in a higher version TiDB.

What is changed and how it works?

check DDLTableVersion >= 2, which is the same as the fixed in the higher version.

Check List

Tests

• Unit test

• Integration test

• Manual test (add detailed scripts or steps below)
  Start a master cluster, then use this PR to start a TiDB server. It can start normally.

• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

 support rollback from higher version to 6.5

[wjhuang2016]

/retest

[Benjamin2037]

Please add UT cover change.

[Benjamin2037]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Benjamin2037, zimulala

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-08-02 09:47:23.765532608 +0000 UTC m=+265127.707881139: ☑️ agreed by Benjamin2037.
• 2023-08-03 02:37:35.63594041 +0000 UTC m=+325739.578288944: ☑️ agreed by zimulala.

[wjhuang2016]

/retest

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (release-6.5@cb6e7cb). Click here to learn what that means.
The diff coverage is n/a.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-6.5     #45762   +/-   ##
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  Coverage               ?   73.6919%           
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  Files                  ?       1083           
  Lines                  ?     347205           
  Branches               ?          0           
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  Hits                   ?     255862           
  Misses                 ?      74937           
  Partials               ?      16406           

[ti-chi-bot]

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