lightning: fix gcs max key limit (#30393)

[ti-srebot]

cherry-pick #30393 to release-5.3
You can switch your code base to this Pull Request by using git-extras:

# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/30560

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/tidb.git pr/30560:release-5.3-bc08b50127f5

---

What problem does this PR solve?

Issue Number: close #30377

Problem Summary: opt.ListCount is the number of keys fetched each time for s3, instead of the limitation.

What is changed and how it works?

ignore opt.ListCount in gcs and directly walk all the keys.

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

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• glorv
• kennytm

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[ti-srebot]

/run-all-tests

[ti-srebot]

@Leavrth please accept the invitation then you can push to the cherry-pick pull requests. Comment with /cherry-pick-invite if the invitation is expired.
https://github.com/ti-srebot/tidb/invitations

[lichunzhu]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: cbc9e3b

[lichunzhu]

/run-check_dev

[lichunzhu]

/run-check_dev