Sdk 5186 add custom email provider support

[acwest]

Changes

This PR adds support for the custom email provider, and updates to the most recent auth0 api.

References

-https://auth0.com/docs/api/management/v2/emails/post-provider

[tusharpandey13]

Hi @acwest, noting that the PR is for the change "add custom email provider support",

1. There are a lot of changes in files unrelated to this feature being pushed in this PR. If we are, in-fact updating these managers and methods, do we have tracking tickets/documentation for these changes? This PR should only contain changes related to this specific feature. To include specific endpoints, you can just replace those JSON nodes during generation process in sdks-oas.
2. I see there are no unit-tests added for this feature. Please add unit tests for all the implemented endpoints, you can follow this file for your reference: self-service-profiles.test.ts. Please add the output of npm run test to your PR description.