Fix running a subset of tests

[AlekSi]

Description

The logic condition was wrong, and the error was hidden.

Readiness checklist

• I added/updated unit tests (and they pass).
• I added/updated integration/compatibility tests (and they pass).
• 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), Milestone (Next), Labels, Project and project's Sprint fields.
• I marked all done items in this checklist.

[codecov]

Codecov Report

Merging #3479 (ddd6c27) into main (85626b8) will decrease coverage by 69.67%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main   #3479       +/-   ##
==========================================
- Coverage   74.30%   4.63%   -69.67%     
==========================================
  Files         422     416        -6     
  Lines       26374   26058      -316     
==========================================
- Hits        19597    1208    -18389     
- Misses       5624   24768    +19144     
+ Partials     1153      82     -1071     

see 326 files with indirect coverage changes

Flag	Coverage Δ
filter-true	4.63% <ø> (-64.68%)	⬇️
hana-1	?
integration	4.63% <ø> (-64.68%)	⬇️
mongodb-1	4.63% <ø> (ø)
pg-1	?
pg-2	?
pg-3	?
postgresql-1	?
postgresql-2	?
postgresql-3	?
sort-false	4.63% <ø> (-64.68%)	⬇️
sqlite-1	?
sqlite-2	?
sqlite-3	?
unit	?

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[chilagrow]

Thanks for this 👍