[native] Add jcenter() as fallback for gradlePluginPortal()
Summary:
In a previous diff I removed jcenter() and replaced it with gradlePluginPortal() since jcenter() is (one day) going to be taken down and has been a source of issues in the past.
However... we're now experiencing issues with the Gradle Plugin Portal: https://status.gradle.com/incidents/9j9bx7nlwwf1
I wonder if adding jcenter() as a fallback will resolve things (at least in the short tun)
NOTE: I plan on reverting this in a few days once whatever intermittent Gradle issue is over.
Test Plan: See if Android CI passes
Reviewers: varun, ashoat, tomek, marcin, rohan, ginsu
Reviewed By: ashoat
Subscribers: abosh
Differential Revision: https://phab.comm.dev/D5551