Android: Apply default jar_excluded_patterns only when necessary

Removes jar filtering from non-prebuilt targets where it is a no-op.

Will attempt to remove filtering from prebuilts in a subsequent CL.

Bug: 398002893
Change-Id: Iddd5202b8b9088c1c47da83a773048495feed6c6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6454574
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Sam Maier <smaier@chromium.org>
Owners-Override: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1447238}
NOKEYCHECK=True
GitOrigin-RevId: dd0bdae428ffd3da3483f4ed16ba7a4d8c1376f5