feat: Add support for Branding Phone Notification Template

[duedares-rvj]

🔧 Changes

• resource/auth0_branding_phone_notification_template: Create and update phone notification templates
• data-source/auth0_branding_phone_notification_template: Retrieve and manage existing phone notification templates
• Added relevant test cases and examples

Example:

resource "auth0_branding_phone_notification_template" "otp_enrollment" {
  type     = "otp_enroll"
  disabled = false
  content {
    from = "+1234567890"
    body {
      text  = "Your enrollment code is: @{code}"
      voice = "Your enrollment code is @{code}"
    }
  }
}

data "auth0_branding_phone_notification_template" "otp_enrollment" {
  template_id = "tem_xxxxxxxxxxxxxxxxx"
}

📚 References

https://auth0.com/docs/api/management/v2/branding/create-phone-template

🔬 Testing

Tests added and recorded
make test FILTER=TestAccDataSourcePhoneNotificationTemplate
make test FILTER=TestAccPhoneNotificationTemplate

📝 Checklist

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

[kushalshit27]

disabled
Should it be computed?

[kushalshit27]

LGTM!