fix endpoint for non-global

[modular-magician]

Fixes #12880

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Release Note Template for Downstream PRs (will be copied)

dialogflowcx: fixed a deployment issue for `google_dialogflow_cx_version` and `google_dialogflow_cx_environment` when they are deployed to a non-global location

Derived from GoogleCloudPlatform/magic-modules#6752

[github-actions]

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