chore: add action to track nr bundle size

[metal-messiah]

This PR adds a GHA to track the main branch bundle size over time by reporting custom events to NR.

Overview

Related Issue(s)

https://new-relic.atlassian.net/browse/NR-251542?atlOrigin=eyJpIjoiNGI1MDM0YzZmZmNjNGM1MmEwODJiN2QwYjY5NTdkMTgiLCJwIjoiaiJ9

Testing

[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	30.13 kB / 10.86 kB (gzip)	30.13 kB / 10.86 kB (gzip)	0% / 0% (gzip)
lite	async-chunk	53.39 kB / 17.35 kB (gzip)	53.39 kB / 17.35 kB (gzip)	0% / 0% (gzip)
pro	loader	51.67 kB / 17.76 kB (gzip)	51.67 kB / 17.76 kB (gzip)	0% / 0% (gzip)
pro	async-chunk	101.99 kB / 31.12 kB (gzip)	101.99 kB / 31.12 kB (gzip)	0% / 0% (gzip)
spa	loader	59.29 kB / 20.1 kB (gzip)	59.29 kB / 20.1 kB (gzip)	0% / 0% (gzip)
spa	async-chunk	116.66 kB / 35.39 kB (gzip)	116.66 kB / 35.39 kB (gzip)	0% / 0% (gzip)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.99%. Comparing base (9395415) to head (12b19cb).
Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1289   +/-   ##
=======================================
  Coverage   88.99%   88.99%           
=======================================
  Files         170      170           
  Lines        7431     7431           
  Branches     1497     1497           
=======================================
  Hits         6613     6613           
  Misses        697      697           
  Partials      121      121           

Flag	Coverage Δ
unit-tests	79.52% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.