feat: use the new API (POST /getToken) for tokenUrl. and improve token renew.

[iamriajul]

Release Notes

• Feature: Using the latest API tokenUrl parameter. Now it hits POST /getToken. Requires agora-token-service higher than or equal to: v1.4.1. (both RTC & RTM)
• Fixed: Previously the SDK wasn't calling the renewToken method of the native side with the right parameter. (both RTC & RTM)

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• The GitHub Actions pass building and linting. Linter returns no warnings or errors.
• The QA checklist below has been completed

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Previously it was hitting the old Deprecated API Endpoints for generating tokens via the optional tokenUrl parameter.

Issue Number: N/A

What is the new behavior?

Currently it will be hitting the new API Endpoint which is POST /getToken

Does this introduce a breaking change?

• Yes

• No

• Impact:
  Users who are using the old agora-token-service (older than v1.4.1) which doesn't have the POST /getToken endpoint and using the tokenUrl parameter for authentication purposes will be having a breaking feature.