DXCDT-590: Interactive custom text prompt selector

[willvedd]

🔧 Changes

Adds an interactive selector for custom text prompts when using the auth0 ul prompts show and auth0 ul prompts update commands.

🔬 Testing

Manual verification only.

📝 Checklist

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

[codecov-commenter]

Codecov Report

Attention: 14 lines in your changes are missing coverage. Please review.

Comparison is base (f9900b1) 72.50% compared to head (8d34cf0) 72.42%.

Files	Patch %	Lines
internal/cli/prompts_custom_text.go	41.66%	12 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #913      +/-   ##
==========================================
- Coverage   72.50%   72.42%   -0.08%     
==========================================
  Files          93       93              
  Lines       12421    12437      +16     
==========================================
+ Hits         9006     9008       +2     
- Misses       2893     2905      +12     
- Partials      522      524       +2     

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