TF: plan -refresh=false for google_compute_ha_vpn_gateway with gcs backend has resource replacement

[akshat-jindal-nit]

Bug: b/376368181
Issue: hashicorp/terraform-provider-google#19978
This particular change is the main culprit of this issue https://screenshot.googleplex.com/79xwUXBEcc5SYAg.
Looks like this issue start occurring from the release v5.40.0 https://screenshot.googleplex.com/367U6wou3dHnzaJ.

Release Note Template for Downstream PRs (will be copied)

bug: Fixed a bug (b/376368181) where `terraform plan -refresh=false` with `google_compute_ha_vpn_gateway` and a GCS backend would incorrectly show a resource replacement. 

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[harshithpatte-g]

@akshat-jindal-nit can repro this issue with a test? Could we add that test?

[akshat-jindal-nit]

@akshat-jindal-nit can repro this issue with a test? Could we add that test?

@harshithpatte-g this particular change is related to terraform plan -refresh=false related changes. I think we don't write any particulars tests for it.
But this TestAccDataSourceComputeHaVpnGateway is running successfully as our changes are intended to impact the default_values only .