feat: Added Username Validation

[ZaBarudo]

No description provided.

[codecov-commenter]

Codecov Report

Merging #10 (ffe7bc1) into main (ef89564) will decrease coverage by 0.92%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##               main      #10      +/-   ##
============================================
- Coverage     48.28%   47.37%   -0.92%     
  Complexity      257      257              
============================================
  Files            79       79              
  Lines          1400     1427      +27     
  Branches        110      125      +15     
============================================
  Hits            676      676              
- Misses          698      725      +27     
  Partials         26       26              

Impacted Files	Coverage Δ
...character/server/exception/RestExceptionHandler.kt	11.11% <0.00%> (-2.23%)	⬇️
...decharacter/server/seeders/DailyChallengeSeeder.kt	22.22% <0.00%> (-0.86%)	⬇️
...lin/delta/codecharacter/server/user/UserService.kt	4.87% <0.00%> (-0.44%)	⬇️
...acter/server/user/public_user/PublicUserService.kt	3.96% <0.00%> (-0.59%)	⬇️

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[Ram-20062003]

Remove comments