Chore: remove direct dependency on google-cloud-shared-config

[zhumin8]

Regarding this #1550
remove this direct dependency so that this repo only needs sdk-platform-java-config dependency.

cc. @diegomarquezp @blakeli0

[diegomarquezp]

Hi @zhumin8, a couple of quick questions. Should this be part of the current release cycle? Why is google-cloud-shared-config unnecessary compared to sdk-platform-java-config?

[cindy-peng]

Hi @zhumin8, I am also wondering the reason for removing this direct dependency. Could you help us understand why it is unnecessary and it is safe to remove google-cloud-shared-config?

[zhumin8]

@cindy-peng sorry for the delay, this message fall through the cracks and I just noticed it.

So sdk-platform-java-config consolidates configs from google-cloud-shared-config and hosts the google-cloud-shared-dependencies version under the google-cloud-shared-dependencies.version property.
That said, this issue is obsolete as I see #1679 recently made the change.