feat: MFE iframe support [POC]

[metal-messiah]

Please add a one-paragraph summary here, suitable for a release notes description. This will help with documentation.

Overview

Please see this HLD diagram which visualizes the data flow

Related Issue(s)

Testing

[github-actions]

Supportability Metric Usage Changes:

No matching changes found

Supportability Metrics .md File Changes:

supportability_metrics.md was changed? false

New supportability metrics require changes to supportability_metrics.md, as well as a new PR to Angler. Please ensure an Angler PR is created and linked to this PR.

[github-actions]

Asset Size Report

Merging this pull request will result in the following asset size changes:

Agent	Asset	Previous Size	New Size	Diff
lite	loader	27.24 kB / 10.2 kB (gzip)	32.48 kB / 12.14 kB (gzip)	19.25% / 18.99% (gzip)
lite	async-chunk	59.82 kB / 19.99 kB (gzip)	56.64 kB / 18.84 kB (gzip)	-5.31% / -5.73% (gzip)
pro	loader	69.99 kB / 24.32 kB (gzip)	72.21 kB / 25.13 kB (gzip)	3.16% / 3.31% (gzip)
pro	async-chunk	97.4 kB / 30.85 kB (gzip)	97.18 kB / 30.82 kB (gzip)	-0.22% / -0.1% (gzip)
spa	loader	72.31 kB / 25.05 kB (gzip)	74.52 kB / 25.84 kB (gzip)	3.07% / 3.17% (gzip)
spa	async-chunk	109.55 kB / 34.07 kB (gzip)	109.33 kB / 34.03 kB (gzip)	-0.2% / -0.11% (gzip)

[codecov]

Codecov Report

❌ Patch coverage is 6.02410% with 156 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.03%. Comparing base (19a36ab) to head (e438935).
⚠️ Report is 26 commits behind head on main.

Files with missing lines	Patch %	Lines
src/interfaces/registered-iframe-entity.js	0.00%	80 Missing and 16 partials ⚠️
src/loaders/configure/iframe-message-handler.js	6.66%	37 Missing and 19 partials ⚠️
src/common/v2/utils.js	55.55%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1752      +/-   ##
==========================================
- Coverage   88.80%   87.03%   -1.78%     
==========================================
  Files         210      212       +2     
  Lines        7617     7780     +163     
  Branches     1565     1610      +45     
==========================================
+ Hits         6764     6771       +7     
- Misses        761      881     +120     
- Partials       92      128      +36     

Flag	Coverage Δ
unit-tests	80.38% <6.02%> (-2.42%)	⬇️

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