expression: remove duplicate element in json_extract function result

[xiongjiwei]

Signed-off-by: xiongjiwei xiongjiwei1996@outlook.com

What problem does this PR solve?

Issue Number: ref #37133

Problem Summary:

because of the ** in json path, the result of json_extract may contain duplicate result, we should remove it

What is changed and how it works?

Check List

Tests

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

Release note

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

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• hawkingrei
• xhebox

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[ti-chi-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/363ed8cb11d51173a2eb733ed3179434c14c4176

[hawkingrei]

/merge

[ti-chi-bot]

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

Commit hash: c3f96b3

[xiongjiwei]

/run-check-issue-triage-complete

[sre-bot]

TiDB MergeCI notify

🔴 Bad News! New failing [1] after this pr merged.
These new failed integration tests seem to be caused by the current PR, please try to fix these new failed integration tests, thanks!

CI Name	Result	Duration	Compare with Parent commit
idc-jenkins-ci-tidb/integration-ddl-test	🟥 failed 1, success 5, total 6	5 min 52 sec	New failing
idc-jenkins-ci/integration-cdc-test	✅ all 36 tests passed	36 min	Fixed
idc-jenkins-ci-tidb/integration-common-test	🟢 all 17 tests passed	14 min	Existing passed
idc-jenkins-ci-tidb/common-test	🟢 all 11 tests passed	12 min	Existing passed
idc-jenkins-ci-tidb/tics-test	🟢 all 1 tests passed	7 min 12 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-2	🟢 all 28 tests passed	6 min 1 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-1	🟢 all 26 tests passed	5 min 13 sec	Existing passed
idc-jenkins-ci-tidb/mybatis-test	🟢 all 1 tests passed	3 min 38 sec	Existing passed
idc-jenkins-ci-tidb/integration-compatibility-test	🟢 all 1 tests passed	3 min 1 sec	Existing passed
idc-jenkins-ci-tidb/plugin-test	🟢 build success, plugin test success	4min	Existing passed