Tweak SQLite backend tests

[AlekSi]

Description

Prevent one kind of tests failure.

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 #3460 (796b34a) into main (3572f9b) will decrease coverage by 0.10%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #3460      +/-   ##
==========================================
- Coverage   74.02%   73.93%   -0.10%     
==========================================
  Files         422      422              
  Lines       26375    26375              
==========================================
- Hits        19525    19500      -25     
- Misses       5704     5730      +26     
+ Partials     1146     1145       -1     

see 7 files with indirect coverage changes

Flag	Coverage Δ
filter-false	?
filter-true	69.18% <ø> (-0.14%)	⬇️
hana-1	?
integration	69.18% <ø> (-0.14%)	⬇️
mongodb-1	4.63% <ø> (ø)
pg-1	40.61% <ø> (-0.04%)	⬇️
pg-2	43.15% <ø> (-0.10%)	⬇️
pg-3	42.90% <ø> (ø)
postgresql-1	∅ <ø> (∅)
postgresql-2	∅ <ø> (∅)
postgresql-3	∅ <ø> (∅)
sort-false	69.18% <ø> (-0.14%)	⬇️
sort-true	?
sqlite-1	39.74% <ø> (+0.02%)	⬆️
sqlite-2	42.37% <ø> (-0.10%)	⬇️
sqlite-3	42.39% <ø> (-0.01%)	⬇️
unit	24.48% <ø> (-0.04%)	⬇️

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

[rumyantseva]

👌

[chilagrow]

🚀