User Settings: Ignore empty language codes & validate

[6543]

• Ignore incorect language codes
• Validate lang code

ref:

• https://codeberg.org/Codeberg/Community/issues/30

[codecov-io]

Codecov Report

Merging #13755 (896f3b4) into master (3512c7e) will decrease coverage by 0.11%.
The diff coverage is 33.33%.

@@            Coverage Diff             @@
##           master   #13755      +/-   ##
==========================================
- Coverage   42.25%   42.14%   -0.12%     
==========================================
  Files         708      708              
  Lines       77168    77173       +5     
==========================================
- Hits        32608    32522      -86     
- Misses      39196    39303     +107     
+ Partials     5364     5348      -16     

Impacted Files	Coverage Δ
modules/auth/user_form.go	39.65% <ø> (ø)
routers/user/setting/profile.go	39.32% <33.33%> (-0.56%)	⬇️
modules/util/timer.go	42.85% <0.00%> (-42.86%)	⬇️
modules/indexer/stats/queue.go	52.94% <0.00%> (-23.53%)	⬇️
models/issue_comment.go	43.50% <0.00%> (-9.22%)	⬇️
modules/indexer/stats/db.go	43.47% <0.00%> (-8.70%)	⬇️
modules/notification/ui/ui.go	84.72% <0.00%> (-8.34%)	⬇️
modules/queue/unique_queue_channel.go	58.06% <0.00%> (-6.46%)	⬇️
modules/notification/mail/mail.go	33.33% <0.00%> (-5.75%)	⬇️
modules/git/commit.go	49.67% <0.00%> (-3.95%)	⬇️
... and 16 more

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[lafriks]

tests seems to fail now

[6543]

@lafriks fixed :)