Added flatten/expand for token_exchange

[duedares-rvj]

1. custom-token-exchange trigger does not support node18-actions as runtime. It only supports node18 and node22. With the present terraform configuration which manipulated node18 input to node18-actions, it was practically impossible to create an action for this trigger with node18 as runtime. A required clause was added to support this and maintain the same functionality for other triggers.
2. Missing expand/flatten rules where added for auth0_client token_exchange param

🔧 Changes

📚 References

🔬 Testing

📝 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: Patch coverage is 82.35294% with 6 lines in your changes missing coverage. Please review.

Project coverage is 89.20%. Comparing base (dd280c5) to head (9a279ab).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/auth0/action/expand.go	57.14%	2 Missing and 1 partial ⚠️
internal/auth0/client/expand.go	83.33%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1145      +/-   ##
==========================================
- Coverage   89.22%   89.20%   -0.02%     
==========================================
  Files         134      134              
  Lines       18296    18329      +33     
==========================================
+ Hits        16324    16351      +27     
- Misses       1395     1399       +4     
- Partials      577      579       +2     

Files with missing lines	Coverage Δ
internal/auth0/client/flatten.go	94.05% <100.00%> (+0.07%)	⬆️
internal/auth0/action/expand.go	80.29% <57.14%> (-1.39%)	⬇️
internal/auth0/client/expand.go	95.16% <83.33%> (-0.28%)	⬇️

[developerkunal]

LGTM