Allow NR Dashboard to be loaded in iFrames

[hardillb]

part of #4689

Description

Allows owner to configure if Dashboards should be embeddable in an iFrame.

First pass allows dashboard to be loaded from anywhere

Has a feature test for nr-launcher of greater than 2.12.0

paired with FlowFuse/nr-launcher#306

Related Issue(s)

#4689

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 78.74%. Comparing base (7a98b70) to head (e5ccd41).
Report is 190 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4900   +/-   ##
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  Coverage   78.74%   78.74%           
=======================================
  Files         323      323           
  Lines       15221    15221           
  Branches     3496     3496           
=======================================
  Hits        11986    11986           
  Misses       3235     3235           

Flag	Coverage Δ
backend	78.74% <ø> (ø)

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[hardillb]

Tested with both DBv1 and DBv2

[hardillb]

Ready for review, but should not be merged until the nr-launcher pr is merged and published (so part of 2.12.0 release)

[Steve-Mcl]

LGTM. Not merging as per request

[hardillb]

@Steve-Mcl thanks, I've tagged you on the nr-launcher side as well for completeness