Allow SSO Configuration to set Session Expiry/Idle

[hardillb]

fixes #6135

Description

Adds Expiry and Idle values in hours to SSO settings.

If not set default to platform wide settings

Related Issue(s)

#6135

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production
• Link to Changelog Entry PR, or note why one is not needed.

Labels

• Includes a DB migration? -> add the area:migration label

[hardillb]

Needs tests and input validators

[codecov]

Codecov Report

❌ Patch coverage is 81.81818% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.86%. Comparing base (d593989) to head (a7c70d5).
⚠️ Report is 71 commits behind head on main.

Files with missing lines	Patch %	Lines
forge/ee/lib/sso/index.js	0.00%	2 Missing ⚠️
forge/ee/routes/sso/auth.js	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6215      +/-   ##
==========================================
+ Coverage   76.79%   76.86%   +0.06%     
==========================================
  Files         384      385       +1     
  Lines       19439    19452      +13     
  Branches     4671     4679       +8     
==========================================
+ Hits        14928    14951      +23     
+ Misses       4511     4501      -10     

Flag	Coverage Δ
backend	76.86% <81.81%> (+0.06%)	⬆️

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