Draft: Update script in the Google Cloud IAM integration

What does this MR do and why?

Update script in the Google Cloud IAM integration

In the Google Cloud IAM integration, replace the command line instructions. The new version uses the gcloud command, which makes it more simple.

Because of the simplified instructions, there is no need to invite a third party person (typically person with Google Cloud admin rights) to the project. Therefore, we removed the invite links.

We also removed the instructions at the top of the connection section. That was again relevant to Google Cloud admins.

Changelog: changed

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Before	After

How to set up and validate locally

1. Emulate SAAS
2. Enable Premium for the flightjs group.
3. Go https://gdk.test:3443/flightjs/Flight/-/settings/integrations/google_cloud_platform_workload_identity_federation/edit
4. Play with the integration.