[wip]importinto: update stats using UpdateStatsMeta

[D3Hunter]

What problem does this PR solve?

Issue Number: close #xxx

Problem Summary:

What changed and how does it work?

previously, we update the stats inside the sessionVars, and depends on the deltaUpdateTickerWorker to update them at regular interval, but in nextgen wen don't have such worker for user ks since we are inside SYSTEM ks, so change to update stats using UpdateStatsMeta.

Check List

Tests

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

TBD

• 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

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[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.1930%. Comparing base (a3d6d9e) to head (b514776).
⚠️ Report is 3 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #63269        +/-   ##
================================================
+ Coverage   72.7884%   73.1930%   +0.4045%     
================================================
  Files          1831       1831                
  Lines        495404     495651       +247     
================================================
+ Hits         360597     362782      +2185     
+ Misses       112870     110983      -1887     
+ Partials      21937      21886        -51     

Flag	Coverage Δ
integration	42.1760% <0.0000%> (?)
unit	72.2652% <75.0000%> (+0.0075%)	⬆️

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

Components	Coverage Δ
dumpling	52.8700% <ø> (ø)
parser	∅ <ø> (∅)
br	46.3407% <ø> (ø)

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