Move instance pages under team namespace

[cstns]

Description

• nest instances routes under the team namespace and remove instances and immersive editor routes from top level routes
• extend the account store feature check getter
• filter out hidden SectionSideMenu options
• refactor the instance settings side navigation options
  • used named routes
  • used the hidden key to hide options
  • switched to the featuresCheck ux store getter
• updated instance routes and passed team slug
• alter e2e tests to use the new instances routes after changing their namespace

Related Issue(s)

part of https://github.com/FlowFuse/flowfuse/issues/4836

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

Labels

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

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 78.15%. Comparing base (e828f4f) to head (6c81560). Report is 1034 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4905   +/-   ##
=======================================
  Coverage   78.15%   78.15%           
=======================================
  Files         340      340           
  Lines       16190    16190           
  Branches     3756     3756           
=======================================
  Hits        12654    12654           
  Misses       3536     3536           

Flag	Coverage Δ
backend	78.15% <ø> (ø)

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[cstns]

Given the high number of changed files, it would be easier to review on a commit basis from the commits tab