bump TiDB Operator to v1.5.4, TiDB to v7.5.3

[csuzhangxc]

What problem does this PR solve?

What is changed and how does it work?

Code changes

• Has Go code change
• Has CI related scripts change

Tests

• Unit test
• E2E test
• Manual test
• No code

Side effects

• Breaking backward compatibility
• Other side effects:

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Release Notes

Please refer to Release Notes Language Style Guide before writing the release note.

[ti-chi-bot]

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[csuzhangxc]

/run-all-tests

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 47.68%. Comparing base (d032996) to head (f7aa7bc).
Report is 18 commits behind head on release-1.5.

❗ There is a different number of reports uploaded between BASE (d032996) and HEAD (f7aa7bc). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (d032996)	HEAD (f7aa7bc)
unittest	1	0

Additional details and impacted files

@@               Coverage Diff                @@
##           release-1.5    #5732       +/-   ##
================================================
- Coverage        61.53%   47.68%   -13.86%     
================================================
  Files              229      221        -8     
  Lines            29331    29982      +651     
================================================
- Hits             18050    14297     -3753     
- Misses            9499    13984     +4485     
+ Partials          1782     1701       -81     

Flag	Coverage Δ
e2e	47.68% <ø> (?)
unittest	?