Declare proguard_dictionary as implicit output of r8

Soong was generating proguard_dictionary, but not marking it as an
output, so ninja would fail with:
ninja: error: 'out/soong/.intermediates/bootable/recovery/tools/recovery_l10n/RecoveryLocalizer/android_common/proguard_dictionary', needed by 'out/target/common/obj/APPS/RecoveryLocalizer_intermediates/proguard_dictionary', missing and no known rule to make it

Fixes: 78770148
Test: mmma bootable/recovery/tools/recovery_l10n
Change-Id: I956f92519ea81d4fb1322114214099d46d734906