feat: supports new notifier_id attribute in alert configuration notifications

[AgustinBettati]

Description

Jira ticket: INTMDB-981

Adds support for new notifier_id attribute in alert configuration notifications. The use case of this attribute is to enable updates of third party notifications without having to provide the original credentials associated to the notification.

Depends on: mongodb/go-client-mongodb-atlas#516

Type of change:

• Bug fix (non-breaking change which fixes an issue). Please, add the "bug" label to the PR.
• New feature (non-breaking change which adds functionality). Please, add the "enhancement" label to the PR.
• Breaking change (fix or feature that would cause existing functionality to not work as expected). Please, add the "breaking change" label to the PR.
• This change requires a documentation update
• Documentation fix/enhancement

Required Checklist:

• I have signed the MongoDB CLA
• I have read the contribution guidelines
• I have added tests that prove my fix is effective or that my feature works per HashiCorp requirements
• I have added any necessary documentation (if appropriate)
• I have run make fmt and formatted my code
• If changes include deprecations or removals, I defined an isolated PR with a relevant title as it will be used in the auto-generated changelog.

Further comments

Testing with local build

Import and modify existing pager duty alert notification

Create pager duty alert configuration using UI:

Making use of "alert_configurations" data source, imported the created notification defining the notifier_id attribute and modifying another attribute (in this case delay_min).

# terraform import mongodbatlas_alert_configuration.HOST_DOWN_33 64c0f3f5ce752426ab9f506b-6523c95ad978345386809055
resource "mongodbatlas_alert_configuration" "HOST_DOWN_33" {
    project_id = "64c0f3f5ce752426ab9f506b"
    event_type = "HOST_DOWN"
    enabled    = true

    notification {
		# delay_min   = 4
    delay_min   = 16
    notifier_id = "6523c95ad978345386809054"
    type_name   = "PAGER_DUTY"
    }
}

Applying changes successfully:

Terraform will perform the following actions:

  # mongodbatlas_alert_configuration.HOST_DOWN_33 will be updated in-place
  ~ resource "mongodbatlas_alert_configuration" "HOST_DOWN_33" {
        id                     = "aWQ=:NjUyM2M5NWFkOTc4MzQ1Mzg2ODA5MDU1-cHJvamVjdF9pZA==:NjRjMGYzZjVjZTc1MjQyNmFiOWY1MDZi"
      ~ updated                = "2023-10-09T09:50:38Z" -> (known after apply)
        # (5 unchanged attributes hidden)

      ~ notification {
          ~ delay_min     = 4 -> 16
            # (5 unchanged attributes hidden)
        }
    }

Plan: 0 to add, 1 to change, 0 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

mongodbatlas_alert_configuration.HOST_DOWN_33: Modifying... [id=aWQ=:NjUyM2M5NWFkOTc4MzQ1Mzg2ODA5MDU1-cHJvamVjdF9pZA==:NjRjMGYzZjVjZTc1MjQyNmFiOWY1MDZi]
mongodbatlas_alert_configuration.HOST_DOWN_33: Modifications complete after 1s [id=aWQ=:NjUyM2M5NWFkOTc4MzQ1Mzg2ODA5MDU1-cHJvamVjdF9pZA==:NjRjMGYzZjVjZTc1MjQyNmFiOWY1MDZi]

Apply complete! Resources: 0 added, 1 changed, 0 destroyed.

UI displayed update alert notification:

[andreaangiolillo]

test are failing

[carriecwk]

Just some small nits here and there!

[carriecwk]

Suggested change

	* `notifier_id` - The notifier id is a system-generated unique identifier assigned to each notification method. This is needed when updating third-party notifications without requiring explicit authentication credentials.
	* `notifier_id` - The notifier id is a system-generated unique identifier assigned to each notification method. This is needed to update third-party notifications without explicit authentication credentials.

[AgustinBettati]

given that this was copied directly from our API docs (https://www.mongodb.com/docs/atlas/reference/api-resources-spec/v2/#tag/Alert-Configurations/operation/createAlertConfiguration within notifications), would it be better to leave as is for consistency?

[github-actions]

Package	Line Rate	Health
github.com/mongodb/terraform-provider-mongodbatlas/mongodbatlas	2%	❌
github.com/mongodb/terraform-provider-mongodbatlas/mongodbatlas/framework/validator	68%	➖
github.com/mongodb/terraform-provider-mongodbatlas/mongodbatlas/util	14%	❌
Summary	3% (271 / 10289)	❌