fix(udf): add retry on UDF connection error

[wangrunji0408]

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What's changed and what's your intention?

This PR adds retries on UDF connection errors, using exponential backoff.

PS. I have tried tokio_retry but it blocks after reaching the limit number of retries without returning an error. I'm not sure if this is an issue with tokio_retry itself. Just record here.

Checklist

• I have written necessary rustdoc comments
• I have added necessary unit tests and integration tests
• I have added fuzzing tests or opened an issue to track them. (Optional, recommended for new SQL features Sqlsmith: Sql feature generation #7934).
• My PR contains breaking changes. (If it deprecates some features, please create a tracking issue to remove them in the future).
• All checks passed in ./risedev check (or alias, ./risedev c)
• My PR changes performance-critical code. (Please run macro/micro-benchmarks and show the results.)

• My PR contains critical fixes that are necessary to be merged into the latest release. (Please check out the details)

Documentation

• My PR needs documentation updates. (Please use the Release note section below to summarize the impact on users)

[stdrc]

Seems we should also test failing 5 times?

[codecov]

Codecov Report

Attention: 15 lines in your changes are missing coverage. Please review.

Comparison is base (ce73e80) 68.31% compared to head (b68ac23) 68.30%.
Report is 2 commits behind head on main.

Files	Patch %	Lines
src/udf/src/error.rs	0.00%	8 Missing ⚠️
src/udf/src/external.rs	0.00%	6 Missing ⚠️
src/expr/core/src/expr/expr_udf.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #13375      +/-   ##
==========================================
- Coverage   68.31%   68.30%   -0.01%     
==========================================
  Files        1523     1523              
  Lines      261730   261739       +9     
==========================================
- Hits       178794   178793       -1     
- Misses      82936    82946      +10     

Flag	Coverage Δ
rust	68.30% <0.00%> (-0.01%)	⬇️

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