Improve proguard whitelister error message.
Improve proguard whitelister error message.

RELNOTES: Improve error messaging when unsupport proguard options are specified at the library level.
PiperOrigin-RevId: 217184210

meteorcloudy/bazel,akira-baruah/bazel,perezd/bazel,bazelbuild/bazel,werkt/bazel,ButterflyNetwork/bazel,dslomov/bazel-windows,aehlig/bazel,aehlig/bazel,safarmer/bazel,dslomov/bazel,dslomov/bazel-windows,twitter-forks/bazel,bazelbuild/bazel,davidzchen/bazel,akira-baruah/bazel,aehlig/bazel,perezd/bazel,werkt/bazel,twitter-forks/bazel,dslomov/bazel-windows,davidzchen/bazel,cushon/bazel,dslomov/bazel-windows,ulfjack/bazel,katre/bazel,perezd/bazel,dslomov/bazel,davidzchen/bazel,dslomov/bazel,ulfjack/bazel,aehlig/bazel,safarmer/bazel,aehlig/bazel,meteorcloudy/bazel,bazelbuild/bazel,meteorcloudy/bazel,safarmer/bazel,werkt/bazel,ulfjack/bazel,bazelbuild/bazel,akira-baruah/bazel,ulfjack/bazel,safarmer/bazel,bazelbuild/bazel,twitter-forks/bazel,dslomov/bazel-windows,katre/bazel,cushon/bazel,meteorcloudy/bazel,twitter-forks/bazel,bazelbuild/bazel,werkt/bazel,perezd/bazel,katre/bazel,dslomov/bazel,safarmer/bazel,perezd/bazel,katre/bazel,dslomov/bazel,katre/bazel,werkt/bazel,ulfjack/bazel,katre/bazel,ButterflyNetwork/bazel,cushon/bazel,twitter-forks/bazel,perezd/bazel,cushon/bazel,ButterflyNetwork/bazel,ulfjack/bazel,dslomov/bazel,dslomov/bazel,ButterflyNetwork/bazel,davidzchen/bazel,dslomov/bazel-windows,davidzchen/bazel,ulfjack/bazel,davidzchen/bazel,werkt/bazel,meteorcloudy/bazel,akira-baruah/bazel,cushon/bazel,meteorcloudy/bazel,meteorcloudy/bazel,ButterflyNetwork/bazel,davidzchen/bazel,safarmer/bazel,twitter-forks/bazel,aehlig/bazel,akira-baruah/bazel,aehlig/bazel,twitter-forks/bazel,perezd/bazel,cushon/bazel,ButterflyNetwork/bazel,akira-baruah/bazel