Allow wss:// connections to MQTT broker in CSP connect-src

[cstns]

Description

• Browsers were blocking wss://mqtt.flowfuse.cloud connections because the broker host was added to connect-src without a scheme. Per the CSP spec, a bare host inherits the protected page's scheme (https), so WebSocket upgrades to wss:// were rejected.
• Explicitly allow both wss:// and https:// schemes for the broker host so the MQTT-over-WebSockets client can connect.

Related Issue(s)

closes #7206

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

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 76.59%. Comparing base (341af46) to head (237d32d).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
forge/forge.js	66.66%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7205   +/-   ##
=======================================
  Coverage   76.59%   76.59%           
=======================================
  Files         405      405           
  Lines       20579    20580    +1     
  Branches     4975     4975           
=======================================
+ Hits        15762    15763    +1     
  Misses       4817     4817           

Flag	Coverage Δ
backend	76.59% <66.66%> (+<0.01%)	⬆️

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