mounter(ticdc): default value convert to the correct data type (#10804)

[ti-chi-bot]

This is an automated cherry-pick of #10804

What problem does this PR solve?

Issue Number: close #10803

What is changed and how it works?

• convert the datum to the specific column type

Check List

Tests

• Unit test
• Integration test

Questions

Will it cause performance regression or break compatibility?

Do you need to update user documentation, design documentation or monitoring documentation?

Release note

`None`

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (release-8.0@ba58ef9). Click here to learn what that means.
The diff coverage is 70.0000%.

Additional details and impacted files

Components	Coverage Δ
cdc	61.8946% <0.0000%> (?)
dm	51.2555% <0.0000%> (?)
engine	63.3794% <0.0000%> (?)

Flag	Coverage Δ
unit	57.5620% <70.0000%> (?)

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

@@               Coverage Diff                @@
##             release-8.0     #10826   +/-   ##
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  Coverage               ?   57.5620%           
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  Files                  ?        853           
  Lines                  ?     126891           
  Branches               ?          0           
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  Hits                   ?      73041           
  Misses                 ?      48413           
  Partials               ?       5437           

[3AceShowHand]

/test cdc-integration-kafka-test

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: 3AceShowHand

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