Refactor muxing 1 : Re-use same config to configure the SDK and PF providers, fix VCR testing

[modular-magician]

Fixes #19197
Fixes #18774
Fixes #20280

Summary

This PR:

• Changes how the plugin-framework implementation of the provider is configured
  • Before: Parallel implementation of configuration logic that parses user inputs and populates a fwtransport.FrameworkProviderConfig struct
  • After: The configure function obtains an already populated transport_tpg.Config struct from the SDK provider, with no duplication of logic to process user inputs.
• Changes code defining the VCR system to accommodate the change above
  • Now the PF provider uses the same Config struct as the SDK provider, both providers can use the same cached configs.
  • This fixes VCR test(s) fail during replay: Framework converted resources #14158 , because a single test will use a single cached client again.
• Makes necessary changes to the data sources currently implemented with the plugin-framework
  • These now expect to receive a transport_tpg.Config struct
  • Any provider-level values are now in the old type system, and require thought about where we convert between those type systems.

Things to pay attention to during review/testing

• What acceptance tests need to be updated now that the PF provider is configured in a SDK-like way?
• Are only changes just to the test required, or do the failures indicate user-facing changes in behaviour?
• Tests
  • 🔴 Acceptance tests for the provider's configuration behaviour are mostly VCR skipped. Testing this PR will require use of TeamCity!
  • Manual testing encouraged
  • We should look at known bugs linked to the muxing and confirm they're gone before merge
    • data.google_dns_managed_zone always fails with "Post "https://oauth2.googleapis.com/token": context canceled" #16832 (comment)
  • After merge, we should closely monitor nightly tests and not rely on the Release Shepherd picking up any failures linked to this PR. Newer tests will provide more signal.

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provider: refactored how the provider configuration is handled internally

Derived from GoogleCloudPlatform/magic-modules#11903