ddl: fix expression index with insert causes losing index data (#26248)

[ti-srebot]

cherry-pick #26248 to release-4.0
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# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/26478

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---

Signed-off-by: wjhuang2016 huangwenjun1997@gmail.com

What problem does this PR solve?

Issue Number: close #26213

Problem Summary:
In reorg, we can't get the value of the hidden virtual column, then the index values are wrong.

What is changed and how it works?

For the hidden virtual column, the state is changed from none to public directly.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• 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

• No release note

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[ti-chi-bot]

@ti-srebot: This cherry pick PR is for a release branch and has not yet been approved by release team.
Adding the do-not-merge/cherry-pick-not-approved label.

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[ti-srebot]

/run-all-tests

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