Fix count's query parameter

[w84thesun]

Description

Readiness checklist

• I added/updated unit tests.
• I added/updated integration/compatibility tests.
• I added/updated comments and checked rendering.
• I made spot refactorings.
• I updated user documentation.
• I ran task all, and it passed.
• I ensured that PR title is good enough for the changelog.
• (for maintainers only) I set Reviewers (@FerretDB/core), Labels, Project and project's Sprint fields.
• I marked all done items in this checklist.

[AlekSi]

It is not a bug because the breaking change wasn't released yet

[codecov]

Codecov Report

Merging #2622 (bbe4e69) into main (11a979f) will decrease coverage by 38.14%.
The diff coverage is n/a.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #2622       +/-   ##
===========================================
- Coverage   65.98%   27.84%   -38.14%     
===========================================
  Files         419      419               
  Lines       20553    20553               
===========================================
- Hits        13561     5724     -7837     
- Misses       6039    14242     +8203     
+ Partials      953      587      -366     

Impacted Files	Coverage Δ
internal/handlers/common/count.go	0.00% <ø> (-100.00%)	⬇️

... and 137 files with indirect coverage changes

Flag	Coverage Δ
integration	5.39% <ø> (-53.48%)	⬇️
mongodb	5.39% <ø> (ø)
pg	?
unit	26.29% <ø> (+0.04%)	⬆️

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