[Refactor] remove name validations for dataset workspaces and usernames

[frascuchon]

Description

This PR removes name pattern validations for datasets, workspaces, and users.

Type of change

• Refactor (change restructuring the codebase without changing functionality)
• Improvement (change adding some improvement to an existing functionality)

How Has This Been Tested

Checklist

• I added relevant documentation
• I followed the style guidelines of this project
• I did a self-review of my code
• I made corresponding changes to the documentation
• I confirm My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have added relevant notes to the CHANGELOG.md file (See https://keepachangelog.com/)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.22%. Comparing base (83996fe) to head (5ebb86e).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #5575      +/-   ##
===========================================
- Coverage    91.30%   91.22%   -0.08%     
===========================================
  Files          145      145              
  Lines         6037     6030       -7     
===========================================
- Hits          5512     5501      -11     
- Misses         525      529       +4     

Flag	Coverage Δ
argilla-server	91.22% <100.00%> (-0.08%)	⬇️

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