[core] Add `test_bundle_size_monitor` back

[oliviertassinari]

Continuous bundle size monitoring, same as mui/mui-x#5550, it's important.

[mj12albert]

Here's a more recent example:

• [material-ui][Rating] Deprecate *Props and complete slots, slotProps (#45295) material-ui#45398 (comment)
• https://mui-dashboard.netlify.app/size-comparison?circleCIBuildNumber=799816&baseRef=v6.x&baseCommit=3bfa70e29b3521f746bbe75d1ee36a31e6a840d4&prNumber=45398

I wonder if there any challenges in measuring it like this, e.g. mentioned in this comment, what do you think? @michaldudak @atomiks