feat: allow enabling global access for PSC endpoints

[Manan-Kothari]

Adds the ability to allow specifying the PSC endpoint as global or not. See https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/compute_forwarding_rule#allow_psc_global_access

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[imrannayer]

/gcbrun

[imrannayer]

/gcbrun