disable static generation on interception routes (#61004)
### What & Why?
Interception routes depend on contextual information that are provided
via request headers. Specifically it needs to know about the
`Next-Router-State-Tree` when generating the interception route RSC
data, which isn't available at build time. This doesn't currently cause
any usage issues, but it erroneously emits static files & RSC payloads
that the client router won't be able to use and will instead fallback to
a dynamic request.
I removed some special case in an existing test since this fix also
resolves a discrepancy in behavior when PPR is turned on
### How?
This excludes interception routes from `appStaticPaths` at builds which
currently determines which pages should be statically generated.
Closes NEXT-2190
