fix: BWOptions.interval accepts number|string

[SgtPooki]

fix #3985

[SgtPooki]

@lidel these tests seem to be failing unrelated to my changes. However, I couldn't get npm install to succeed locally; I assumed due to M1 issues 😬

[achingbrain]

I have an M1, things install fine for me - what's the error message you are seeing on install?

The build is failing because during the esbuild step it's hitting this line and failing to resolve the node 'path' module.

This is likely because something in the dep tree had it previously and now does not which means it only worked previously by coincidence. Oops.

The quick fix is either to add the path polyfill to aegir or to add "path": false to the browser overrides, but the better fix might be to work out why the resolve module is getting referenced during the browser build in the first place since it should only really be loaded from node.

[BigLep]

@SgtPooki : can you please respond with next steps so we can close this or get it across the line?