feat: add log to searcher plugin

[gaius-qi]

Description

• Add log to searcher plugin.

Related Issue

Motivation and Context

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation Update (if none of the other choices apply)

Checklist

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[codecov]

Codecov Report

Merging #2231 (ff6a07d) into main (b9a6c7d) will decrease coverage by 0.01%.
The diff coverage is 41.66%.

@@            Coverage Diff             @@
##             main    #2231      +/-   ##
==========================================
- Coverage   49.69%   49.68%   -0.01%     
==========================================
  Files         145      145              
  Lines       19317    19318       +1     
==========================================
- Hits         9600     9599       -1     
- Misses       9126     9127       +1     
- Partials      591      592       +1     

Flag	Coverage Δ
Object-compatibility-e2etests	?
e2etests	?
unittests	49.68% <41.66%> (-0.01%)	⬇️

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

Impacted Files	Coverage Δ
manager/rpcserver/manager_server_v1.go	0.00% <0.00%> (ø)
manager/rpcserver/manager_server_v2.go	0.00% <0.00%> (ø)
manager/searcher/searcher.go	81.45% <50.00%> (ø)

... and 2 files with indirect coverage changes