Dist unbundled proguard zips with soong

For soong-only builds.

Bug: 413145177
Test: COVERAGE_MODULES="DOCUMENTSUI" TARGET_RELEASE=mainline_2025_06 TARGET_BUILD_VARIANT=userdebug PRODUCT=mainline_modules_x86_64 MODULE_RELEASED_PLATFORM=R ./vendor/google/build/build_unbundled_coverage_mainline_module.sh
Change-Id: I925d64c684402b084572537cde1435a843322dc8