fix: wait_for_function with polling interval

[mxschmitt]

Fixes #1584

[johnhawkinson]

I must admit I'm a little confused; initially I thought that this parameter checking occurred in the playwright driver, but I see now I was looking at the Javascript client (playwright-core/src/client/frame.ts) rather than the driver server (playwright-core/src/server/frames.ts?). If that's even the right terminology.

It's a bit disconcerting to realize there does not seem to be any mechanism, generally speaking, to ensure that parameters are consistently handled across different frontends. It suggests to me there ought to be some kind of automated testing framework that generates parameters from a spec (maybe being the server spec or the javascript frontend?) and validates that all those parameters exist in all of the frontends. Sounds like a huge task, maybe impractical, I dunno.

Anyhow, thank you for this fix.