Bump NetworkStack to target SDK 34

Bump NetworkStack to become NetworkStackNext, and create api35 shims
that are only included in the new NetworkStackNext.

This is a no-op on devices currently in the field as they use SDK 33
and there are no behavior changes affecting NetworkStack in 33

NetworkStackNext was also used until now by development API 34 builds,
so they will see no change either.

Ignore-AOSP-First: topic can't go to AOSP as-is, will cherrypick
Test: TH
Bug: 280250560
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:22c360071be5518acce71d55e79e9c308dd4b792)
Merged-In: I8264dba7cddd515aade669fda869013b41a1fa7f

Change-Id: I8264dba7cddd515aade669fda869013b41a1fa7f
42 files changed