build: transpile dependencies for old browsers

[digitalcora]

No description provided.

[digitalcora]

@robbie-sundstrom I expect this will be required to successfully deploy a new DUP package, assuming what we've been told about the browser environment is correct (that it's still a fork of Chrome 51). Our current versions of React and Sentry, and maybe others, don't support browsers this old anymore.

I am still curious why the User-Agent for data requests from DUPs implies they're all running Chrome 117, so this could also be a test of sorts: Build a package from main, build a package from this branch, and send them both in for testing.

[robbie-sundstrom]

@digitalcora just going through all the PRs open in this repo and realize this one can be closed. Thanks for the initial work here, but the finalized updates to webpack that were needed to get a working DUP package are now captured in this PR - #2800