Fail the build on translations whose placeholders drift

[gpunto]

Goal

Follow-up to #6695, which fixed a crash on v6 caused by an Italian translation reading canale% 1$s.
Lint reports that as StringFormatCount, but the check is a warning by default, so ./gradlew lint
stayed green and the broken string shipped.

Closes AND-1529

Implementation

• Promote StringFormatCount to an error for every Android module, in the root build.gradle.kts
  next to the existing shared lint config. A translation whose placeholders drift from the default
  locale now fails the build instead of adding a line to a report nobody opens.
• Carry over the two %1d spellings still left in stream-chat-android-docs and the XML sample,
  spotted in review on Fix malformed format specifiers in localized strings #6695. Single argument strings, so nothing renders differently.

Scoped to this one check rather than warningsAsErrors, which would pull in the existing backlog
(121 warnings in the Compose module alone).

Testing

• ./gradlew lint passes across every module. No StringFormat finding exists anywhere today, so
  the promotion starts from a clean slate.
• Injected both shapes of the original defect into an Italian string, the misplaced space and the
  full width ％, and confirmed the build now fails on each with StringFormatCount. Reverted after.

[github-actions]

PR checklist ✅

All required conditions are satisfied:

• Title length is OK (or ignored by label).
• At least one pr: label exists.
• Sections ### Goal, ### Implementation, and ### Testing are filled, or the PR is bot-authored.
• An issue is linked (Linear ticket or GitHub issue), or the PR is bot-authored.

🎉 Great job! This PR is ready for review.

[github-actions]

SDK Size Comparison 📏

SDK	Before	After	Difference	Status
stream-chat-android-client	6.09 MB	6.09 MB	0.00 MB	🟢
stream-chat-android-ui-components	11.40 MB	11.40 MB	0.00 MB	🟢
stream-chat-android-compose	13.07 MB	13.07 MB	0.00 MB	🟢

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud