ci/android: strip the artifacts of the debian-android job

The libraries built in the `debian-android` job are not stripped because
the job defines `ARTIFACTS_DEBUG_SYMBOLS: 1`.

However this is not strictly necessary for testing purposes, so stop
defining `ARTIFACTS_DEBUG_SYMBOLS` to reduce the size of the artifacts.

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/12879
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34234>

.gitlab-ci/build/gitlab-ci.yml

@@ -419,7 +419,6 @@ debian-android:
       -D install-mesa-clc=true
       -D precomp-compiler=enabled
       -D install-precomp-compiler=true
-    ARTIFACTS_DEBUG_SYMBOLS: 1
     S3_ARTIFACT_NAME: mesa-x86_64-android-${BUILDTYPE}
   script:
     # x86_64 build: