statistics: add new DDL event for stats handler

[Rustin170506]

What problem does this PR solve?

Issue Number: ref #48126 (comment)

Problem Summary:

What is changed and how it works?

• Added new DDL event for stats handler. You can see Tracking Issue for Partition Statistics #48126 (comment) to check why we need these fields and information.

Check List

Tests

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

  • I checked and no code files have been changed.

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.

None

[codecov]

Codecov Report

Merging #48361 (fb815d2) into master (662528d) will increase coverage by 1.9404%.
Report is 17 commits behind head on master.
The diff coverage is n/a.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #48361        +/-   ##
================================================
+ Coverage   71.3789%   73.3193%   +1.9404%     
================================================
  Files          1402       1426        +24     
  Lines        406735     417014     +10279     
================================================
+ Hits         290323     305752     +15429     
+ Misses        96491      92278      -4213     
+ Partials      19921      18984       -937     

Flag	Coverage Δ
integration	43.7127% <ø> (?)
unit	71.9004% <ø> (+0.5214%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	53.9874% <ø> (ø)
parser	∅ <ø> (∅)
br	48.7075% <ø> (-4.2054%)	⬇️

[Rustin170506]

🔢

[hawkingrei]

/ok-to-test

[time-and-fate]

This will replace pkg/ddl/util/event.go, right?

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: qw4990, time-and-fate

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Needs approval from an approver in each of these files:

• OWNERS [qw4990,time-and-fate]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-11-08 03:24:57.311045687 +0000 UTC m=+3614694.898155817: ☑️ agreed by qw4990.
• 2023-11-08 04:32:29.301872441 +0000 UTC m=+3618746.888982584: ☑️ agreed by time-and-fate.

[Rustin170506]

/retest