Add GKE credential to jenkinsfile

[IsaSih]

Summary

ATTENTION!!
Depends on rancherlabs/corral-packages#71 to be merged in the corral-packages repo

Fixes #rancher/qa-tasks#1641
Supports e2e tests in #12934 by Adding the GKE credentials to the jenkins file

Occurred changes and/or fixed issues

GKE cred was stored in the secrets manager with the jenkins identifier tag for the e2e tests that validate GKE cluster provisioning to be executed in the pipeline that stores cloud credentials

Areas or cases that should be tested

Run all e2e tests via the jenkins pipeline

Areas which could experience regressions

Cluster provisioning tests
Cloud credentials creation tests
Any other tests that rely on authentication with cloud credentials

Checklist

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[yonasberhe23]

LGTM!

[IsaSih]

ATTENTION! Please, don't merge this PR before rancherlabs/corral-packages#71 is merged

[izaac]

let's make the CI pass and it's good to go

[izaac]

ATTENTION! Please, don't merge this PR before rancherlabs/corral-packages#71 is merged

Not an issue, here an env variable is just getting set, I don't think it will impact the corral package

[izaac]

@IsaSih @yonasberhe23 We need to update the multi recurring job too I believe https://github.com/rancher/dashboard/blob/master/cypress/jenkins/Jenkinsfile_multi

[izaac]

See multi Jenkins file comment.

[izaac]

My bad @IsaSih those credentials are handled automatically by the pipeline and passed to their executors.