Improve feedback when Hosted Instances are not available to a team

[joepavitt]

Description

Improves communication to user that Hosted Instances are unavailable on their Free Tier, as well as refining the UX path to Devices when a new Application is created and prevent the current confusion caused by users being redirected to /instances when it's not something they're able to use.

• Shows a "Premium" flag for "Hosted Instances" in the side navigation when 0 instances are permitted on tat given Team Type
• Auto-redirects to the ApplicationDevices screen when navigating to the base page for an Application, if no Instances are allowed to be created. This includes newly created applications on the Free Tier.
• Ensure we show the "Feature Unavailable" banner on the Application - Instances page if a user does navigate there
• Fix the router-link :to fields for the Instance and Device empty state placeholders on the Applications home page
• Prevent the option for "Create Node-RED Instance" when creating a new application in a team that isn't permitted to create an instance
• Prevent option to "Create Instance with Application" if the Team Tier does not permit it
• Improve language in the help text

Screenshots

Related Issue(s)

Closes #4955

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]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.44%. Comparing base (d29e97d) to head (0c84d0a).
Report is 3 commits behind head on main.

Additional details and impacted files

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  Coverage   78.44%   78.44%           
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  Files         325      325           
  Lines       15353    15353           
  Branches     3529     3529           
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  Hits        12043    12043           
  Misses       3310     3310           

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[cstns]

Looking good overall, would love some basic e2e coverage nothing fancy. I'll approve the pr as is and you can add the tests later as i won't be here to approve