Auto-format //android_webview GN files

Run "gn format" and automatically shorten target references, now that GN
knows how to do this. Then manually delete duplicate entries in the
output.

Bug: 40760278
Change-Id: I909509affe60b7f7f313a00dd8a1e9254604e70c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6785710
Auto-Submit: Lei Zhang <thestig@chromium.org>
Commit-Queue: Peter Conn <peconn@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Peter Conn <peconn@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1491889}