Remove google_project_service from state if not found

[c2thorn]

Fixes hashicorp/terraform-provider-google#9841

This PR reverses the change introduced in the sdkv2 upgrade: https://github.com/hashicorp/terraform-provider-google/blame/d1014fe3b47d377db9a6eee9cfa9cbb0412c18e2/google/resource_google_project_service.go#L190

If a service was disabled outside of TF, the previous change showed a permanent error and would not let users re-enable the service until it was removed from state and added back to the config.

If this PR is for Terraform, I acknowledge that I have:

• Searched through the issue tracker for an open issue that this either resolves or contributes to, commented on it to claim it, and written "fixes {url}" or "part of {url}" in this PR description. If there were no relevant open issues, I opened one and commented that I would like to work on it (not necessary for very small changes).
• Generated Terraform, and ran make test and make lint to ensure it passes unit and linter tests.
• Ensured that all new fields I added that can be set by a user appear in at least one example (for generated resources) or third_party test (for handwritten resources or update tests).
• Ran relevant acceptance tests (If the acceptance tests do not yet pass or you are unable to run them, please let your reviewer know).
• Read the Release Notes Guide before writing my release note below.

Release Note Template for Downstream PRs (will be copied)

serviceusage: fixed an issue in `google_project_service` where users could not reenable services that were disabled outside of Terraform.

[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, 2 insertions(+), 9 deletions(-))
Terraform Beta: Diff ( 1 file changed, 2 insertions(+), 9 deletions(-))

[modular-magician]

I have triggered VCR tests in RECORDING mode for the following tests that failed during VCR: TestAccComputeOrganizationSecurityPolicyRule_organizationSecurityPolicyRuleUpdateExample|TestAccFirebaseWebApp_firebaseWebAppBasicExample You can view the result here: https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=204930

[modular-magician]

Tests failed during RECORDING mode: TestAccFirebaseWebApp_firebaseWebAppBasicExample Please fix these to complete your PR