fix(async search): don't launch intervals in goroutines

[forshev]

Description

Don't launch intervals in goroutines when doing async search.

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 20.00000% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 71.53%. Comparing base (94e5bd0) to head (6be1b9d).

Files with missing lines	Patch %	Lines
asyncsearcher/async_searcher.go	20.00%	6 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #506      +/-   ##
==========================================
- Coverage   71.56%   71.53%   -0.03%     
==========================================
  Files         239      239              
  Lines       20158    20150       -8     
==========================================
- Hits        14426    14415      -11     
  Misses       4652     4652              
- Partials     1080     1083       +3     

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