project_service update to read/acquire a service on create

[c2thorn]

Instead of trying to enable the API every time on Create, I added a read to check if the API was already enabled first.

Release Note Template for Downstream PRs (will be copied)

`google_project_service` will no longer attempt to enable a service that is already enabled.

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 1 file changed, 18 insertions(+), 4 deletions(-))
Terraform Beta: Diff ( 1 file changed, 18 insertions(+), 4 deletions(-))

[danawillow]

Since this is a behavior change, can you add a release note? I think enhancement will be good. It would also be good to have this behavior documented in the project_service docs just to be explicit that it's intentional.

This doesn't have a GH issue open for it, does it?

[c2thorn]

Updated! The docs already had a little blurb that was relevant, so I just modified it to say "verify" instead of "re-enable" an already enabled service.

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 2 files changed, 19 insertions(+), 5 deletions(-))
Terraform Beta: Diff ( 2 files changed, 19 insertions(+), 5 deletions(-))