Add an alias to jni_zero::AdoptRef and CreateLeaky in webrtc

Recently, JNI Zero has introduced two helper functions:
1. jni_zero::AdoptRef() which constructs a ScopedJavaLocalRef
2. jni_zero::CreateLeaky() which constructs a JavaRef

This CL adds aliases to these two functions in the webrtc namespace.
These aliases will be used later in google3.

Bug: chromium:481689330
Change-Id: I42f91ec95b2a6059335733fc95af046af5dfa80b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/466660
Commit-Queue: Martin Kong <martinkong@google.com>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Evan Shrubsole <eshr@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47555}