fix(optimizer): fix apply join rule corrupted by refactor

[chenzl25]

I hereby agree to the terms of the Singularity Data, Inc. Contributor License Agreement.

What's changed and what's your intention?

PLEASE DO NOT LEAVE THIS EMPTY !!!

Please explain IN DETAIL what the changes are in this PR and why they are needed:

• style: fix warnings on latest clippy #5876 has corrupted ApplyJoinRule.

Checklist

• I have written necessary rustdoc comments
• I have added necessary unit tests and integration tests
• All checks passed in ./risedev check (or alias, ./risedev c)

Documentation

If your pull request contains user-facing changes, please specify the types of the changes, and create a release note. Otherwise, please feel free to remove this section.

Types of user-facing changes

Please keep the types that apply to your changes, and remove those that do not apply.

• Installation and deployment
• Connector (sources & sinks)
• SQL commands, functions, and operators
• RisingWave cluster configuration changes
• Other (please specify in the release note below)

Release note

Please create a release note for your changes. In the release note, focus on the impact on users, and mention the environment or conditions where the impact may occur.

Refer to a related PR or issue link (optional)

#5876

[codecov]

Codecov Report

Merging #6554 (5ba49d6) into main (2d87383) will decrease coverage by 0.09%.
The diff coverage is 78.21%.

@@            Coverage Diff             @@
##             main    #6554      +/-   ##
==========================================
- Coverage   74.07%   73.98%   -0.10%     
==========================================
  Files         989      993       +4     
  Lines      161850   162235     +385     
==========================================
+ Hits       119888   120022     +134     
- Misses      41962    42213     +251     

Flag	Coverage Δ
rust	73.98% <78.21%> (-0.10%)	⬇️

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

Impacted Files	Coverage Δ
src/batch/src/error.rs	0.00% <ø> (ø)
src/common/src/catalog/schema.rs	78.12% <0.00%> (-6.34%)	⬇️
src/compute/src/server.rs	0.00% <0.00%> (ø)
src/expr/src/error.rs	25.00% <ø> (ø)
src/expr/src/expr/template.rs	67.00% <ø> (ø)
src/expr/src/vector_op/to_char.rs	0.00% <0.00%> (ø)
src/frontend/src/catalog/root_catalog.rs	72.76% <0.00%> (-2.52%)	⬇️
src/frontend/src/handler/drop_index.rs	59.70% <0.00%> (-5.88%)	⬇️
src/frontend/src/handler/drop_source.rs	0.00% <0.00%> (-85.15%)	⬇️
src/risedevtool/src/config.rs	0.00% <0.00%> (ø)
... and 94 more

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[xxchan]

😇 (It's not covered by any test case?

[chenzl25]

😇 (It's not covered by any test case?

Our system basically wouldn't generate an intermediate apply operator containing on condition when it meets this rule. I am trying to do some refactoring about subquery unnesting, after that it will be covered by test cases.