Allow to change SQLite URI in tests

[AlekSi]

Description

Useful for task env-data.

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), Labels, Project and project's Sprint fields.
• I marked all done items in this checklist.

[codecov]

Codecov Report

Merging #3092 (edb6563) into main (eb5addc) will increase coverage by 0.08%.
The diff coverage is 86.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3092      +/-   ##
==========================================
+ Coverage   76.55%   76.63%   +0.08%     
==========================================
  Files         388      389       +1     
  Lines       21297    21307      +10     
==========================================
+ Hits        16303    16328      +25     
+ Misses       4065     4053      -12     
+ Partials      929      926       -3     

Impacted Files	Coverage Δ
integration/setup/setup.go	79.77% <ø> (ø)
internal/backends/sqlite/metadata/pool/db.go	67.74% <ø> (ø)
integration/setup/startup.go	67.81% <75.00%> (-0.94%)	⬇️
integration/setup/listener.go	72.32% <80.00%> (-0.46%)	⬇️
internal/backends/sqlite/metadata/pool/uri.go	90.62% <90.62%> (ø)
internal/backends/sqlite/metadata/pool/pool.go	84.76% <100.00%> (-1.17%)	⬇️

... and 6 files with indirect coverage changes

Flag	Coverage Δ
hana	?
integration	73.16% <50.00%> (+0.08%)	⬆️
mongodb	5.46% <0.00%> (-0.03%)	⬇️
pg	66.40% <6.00%> (-0.07%)	⬇️
shard-1	57.02% <50.00%> (+0.09%)	⬆️
shard-2	55.10% <50.00%> (+<0.01%)	⬆️
shard-3	57.14% <50.00%> (-0.02%)	⬇️
sqlite	46.51% <48.00%> (+0.09%)	⬆️
unit	24.08% <90.90%> (+<0.01%)	⬆️

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

[noisersup]

Looks useful!