Fix `revalidateTag()` behaviour when invoked in server components (#70446) (#70642)
This backports #70446 to 14-2-1
Fixes #70403
### What?
When `revalidateTag()` is called directly in server components, the
cache is not purged for the corresponding tags. Reproduction steps
available in #70403
### How?
Check
[app-render.tsx](https://github.com/vercel/next.js/compare/canary...abhi12299:fix-revalidatetag-rsc?expand=1#diff-a3e2e024db1faa1b501e0dd6040eaaf0d931cb9878ae0fb0f4c3658daa982768)
This issue was introduced in #65296 in this file:
[revalidate.ts](https://github.com/vercel/next.js/pull/65296/files#diff-7f0cb5bb30d44b9153d724e31c25859b9aab6cc258b35563a1d9464cd0688283).
The lines removed from the file resulted in the revalidation checks to
be skipped when there is an RSC request.
Also fixed checks on `pendingRevalidates` to also check for
`revalidatedTags`.
Co-authored-by: Abhishek Mehandiratta <36722596+abhi12299@users.noreply.github.com>