Align google_recaptcha_enterprise_key samples with customer use cases

[rileykarson]

A service team member flagged that many of the configuration options on the reference page don't make sense, and don't align with real-world use cases. While we want to display examples of the options of the resource, we should limit uncommon options to 1-2 examples rather than all of them.

Specific notes:

• Allowed package names should be used rather than the allow_all_package_names boolean
• testing_options makes a key non-prod
• Labels can be omitted from most examples

Resource: google_recaptcha_enterprise_key
Page: https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/recaptcha_enterprise_key