* Rename `provider` to `providerConfig`
The network controller `provider` state has been renamed to
`providerConfig`. This better reflects what this state is, and makes
this controller more closely aligned with the core network controller.
All references to the provider configuration have been updated to
prefer `providerConfig` over `provider`, to make the distinction clear
between a provider and provider config.
Closes#18902
* Add migration
* Use network provider state, instead of CurrencyRateController state, select 'nativeCurrency'
* Fix unit tests
* Lint fix
* Only use the network provider ticket for the native currency when useCurrencyRateCheck is false
* Fix unit test
* Fix tests for real
