custom.js: fix invalid CSS selector in VAT country sync

[Sumit-Sabhaya]

Fixes #4307

In weblate_web/static/custom.js, the VAT form selector contained a
U+00B7 MIDDLE DOT (·) instead of a descendant combinator (space):

`#id_country·option[value="${value}"]`

This made querySelector() return null, throwing
TypeError: Cannot set properties of null (setting 'selected') whenever the
VAT country field changed, so the country <select> was never synced.

Fix: replace the middle dot with a space.

[nijel]

@codex review

[nijel]

Scheduled for merge, thanks for your contribution!

[Sumit-Sabhaya]

@nijel Waiting For Approval.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.81%. Comparing base (4424e0f) to head (9a11116).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4308      +/-   ##
==========================================
- Coverage   91.85%   91.81%   -0.05%     
==========================================
  Files          76       76              
  Lines       16692    16692              
  Branches     1404     1404              
==========================================
- Hits        15333    15325       -8     
- Misses        943      949       +6     
- Partials      416      418       +2     

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[Sumit-Sabhaya]

@nijel Thanks For Quickly Merge Can i have delete this fork ?