fix: re-apply prompt settings after branding update to prevent Authentication Profile reset

[harshithRai]

When PATCH /api/v2/branding is called without a colors field, the Auth0 Management API silently resets the tenant's Authentication Profile (identifier_first) from "Identifier First" to "Identifier + Password". This affects any user importing a branding config that doesn't include colors.

A partial fix was shipped in v8.29.3 that reapplied prompt settings after branding, but only when prompts was present in the user's config. This fix closes the gap for the case where prompts is not managed in the config at all.

🔧 Changes

In the branding handler, prompt settings are now snapshotted before the branding PATCH and immediately re-applied after, undoing the API side-effect regardless of whether the tenant has colors configured or whether prompts is in the user's config.

No changes to the YAML or JSON config shape, this is purely an internal fix with no impact on existing configurations.

📚 References

• Fixes Importing branding without colors resets Authentication Profile to "Identifier + Password" #1402
• Related prior fix: Fix: Universal Login Authentication Profile reverts to Identifier+Password after import  #1333
• Same API behavior confirmed in terraform-provider-auth0: auth0_branding with only logo_url silently resets authentication profile settings terraform-provider-auth0#1510

🔬 Testing

• Unit tests added to test/tools/auth0/handlers/branding.tests.js covering scenarios where:
  • the prompt settings snapshot/restore flow and call order
  • Branding update still succeeds if prompt settings fetch fails
• Manually verified on a real tenant:
  • Set Authentication Profile to "Identifier First" via dashboard
  • Ran a0deploy import with a branding config containing only logo_url and no colors
  • Confirmed Authentication Profile remains "Identifier First" after import

📝 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

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.19%. Comparing base (431f0b2) to head (5c1226e).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1404   +/-   ##
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  Coverage   80.18%   80.19%           
=======================================
  Files         153      153           
  Lines        7116     7119    +3     
  Branches     1572     1573    +1     
=======================================
+ Hits         5706     5709    +3     
  Misses        760      760           
  Partials      650      650           

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