Not allow comma for the user name

[AllForNothing]

1. Not allow comma for the user name when creating a user

Thank you for contributing to Harbor!

Comprehensive Summary of your change

Issue being fixed

Fixes #(issue)

Please indicate you've done the following:

• Well Written Title and Summary of the PR
• Label the PR as needed. "release-note/ignore-for-release, release-note/new-feature, release-note/update, release-note/enhancement, release-note/community, release-note/breaking-change, release-note/docs, release-note/infra, release-note/deprecation"
• Accepted the DCO. Commits without the DCO will delay acceptance.
• Made sure tests are passing and test coverage is added if needed.
• Considered the docs impact and opened a new docs issue or PR with docs changes if needed in website repository.

[codecov]

Codecov Report

Merging #19501 (f872f10) into main (61fdf25) will increase coverage by 0.00%.
Report is 1 commits behind head on main.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main   #19501   +/-   ##
=======================================
  Coverage   67.43%   67.44%           
=======================================
  Files         989      989           
  Lines      108836   108836           
  Branches     2752     2752           
=======================================
+ Hits        73398    73404    +6     
+ Misses      31479    31468   -11     
- Partials     3959     3964    +5     

Flag	Coverage Δ
unittests	67.44% <ø> (+<0.01%)	⬆️

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

see 8 files with indirect coverage changes