install/0000_30_machine-api-operator_00_credentials-request: Set skipServiceCheck again for GCP

Checking history:

  $ git --no-pager log -G skipServiceCheck -p --format='commit %h %s' install/0000_30_machine-api-operator_00_credentials-request.yaml | grep 'commit\|skipServiceCheck'
  commit 3db6326f stop using beta pre-defined role for compute.targetPools
  -    skipServiceCheck: true
  commit c4c80c84 GCP CI runs are complaining about APIs not being enabled
  +    skipServiceCheck: true

But even with 3db6326f (stop using beta pre-defined role for
compute.targetPools, 2021-11-10, #950)'s pivot to roles/compute.admin,
we can still get bit by changes like [1]:

  Upcoming IAM changes for the week of 2024-10-21
  ...
  Compute Engine
  The following permissions have been added to the Compute Admin role (roles/compute.admin):

  backupdr.backupPlanAssociations.create
  backupdr.backupPlanAssociations.createForComputeInstance
  ...

resulting in failures issues like [2]:

  level=error msg=Cluster operator cloud-credential Degraded is True with CredentialsFailing: 2 of 7 credentials requests are failing to sync.
  level=info msg=Cluster operator cloud-credential Progressing is True with Reconciling: 5 of 7 credentials requests provisioned, 2 reporting errors.
  ...
  level=error msg=Cluster operator machine-api Degraded is True with SyncingFailed: Failed when progressing towards operator: 4.14.0-0.nightly-2024-10-25-153502 because minimum worker replica count (2) not yet met: current running replicas 0, waiting for [ci-op-nsl57y3j-c731f-8rp6f-worker-a-bhp4m ci-op-nsl57y3j-c731f-8rp6f-worker-b-79b5s ci-op-nsl57y3j-c731f-8rp6f-worker-c-xwhp9]
  level=error msg=Cluster operator machine-api Available is False with Initializing: Operator is initializing
  ...
  level=error msg=failed to initialize the cluster: Cluster operators authentication, console, control-plane-machine-set, image-registry, ingress, machine-api, monitoring are not available Installer exit with code 6

and:

  $ oc -n openshift-cloud-credential-operator get -o json credentialsrequests | jq -r '.items[] | .metadata.name as $n | .spec.providerSpec.skipServiceCheck as $s | .status | (.conditions // [])[] | select(.reason == "CredentialsProvisionFailure") | $n + " skipServiceCheck:" + ($s | tostring) + " " + .message'
  openshift-cloud-network-config-controller-gcp skipServiceCheck:null failed to grant creds: not all required service APIs are enabled
  openshift-machine-api-gcp skipServiceCheck:null failed to grant creds: not all required service APIs are enabled

With this commit, I'm restoring the skip request, so cluster
administrators don't have to enable backupdr and other permissions not
needed by the Machine API.

4.15 and later have 39bd33af (Revert "Revert custom role",
2023-11-27, #1178), so they are not exposed to these shifting role
definitions.

[1]: https://cloud.google.com/iam/docs/permissions-change-log
[2]: https://prow.ci.openshift.org/view/gs/test-platform-results/logs/periodic-ci-openshift-release-master-ci-4.14-e2e-gcp-ovn/1849838522425413632