Document on_streaming_backlog_exceeded in email/webhook notifications in databricks_job (#4660)

## Changes
<!-- Summary of your changes that are easy to understand -->

Resolves #4659


## Tests
<!-- 
How is this tested? Please see the checklist below and also describe any
other relevant tests
-->

- [x] relevant change in `docs/` folder

Author: alexott

NEXT_CHANGELOG.md

@@ -13,6 +13,7 @@
 
  * Document `performance_target` in `databricks_job` ([#4651](https://github.com/databricks/terraform-provider-databricks/pull/4651))
  * Add more examples for `databricks_model_serving` ([#4658](https://github.com/databricks/terraform-provider-databricks/pull/4658))
+ * Document `on_streaming_backlog_exceeded` in email/webhook notifications in `databricks_job` ([#4660](https://github.com/databricks/terraform-provider-databricks/pull/4660))
  * Refresh `spark_python_task` option in `databricks_job` ([#4666](https://github.com/databricks/terraform-provider-databricks/pull/4666))
 
 ### Exporter

docs/resources/job.md

@@ -458,6 +458,7 @@ This block can be configured on both job and task levels for corresponding effec
 * `on_success` - (Optional) (List) list of emails to notify when the run completes successfully.
 * `on_failure` - (Optional) (List) list of emails to notify when the run fails.
 * `on_duration_warning_threshold_exceeded` - (Optional) (List) list of emails to notify when the duration of a run exceeds the threshold specified by the `RUN_DURATION_SECONDS` metric in the `health` block.
+* `on_streaming_backlog_exceeded` - (Optional) (List) list of emails to notify when any streaming backlog thresholds are exceeded for any stream.
 
 The following parameter is only available for the job level configuration.
 
@@ -471,6 +472,7 @@ Each entry in `webhook_notification` block takes a list `webhook` blocks. The fi
 * `on_success` - (Optional) (List) list of notification IDs to call when the run completes successfully. A maximum of 3 destinations can be specified.
 * `on_failure` - (Optional) (List) list of notification IDs to call when the run fails. A maximum of 3 destinations can be specified.
 * `on_duration_warning_threshold_exceeded` - (Optional) (List) list of notification IDs to call when the duration of a run exceeds the threshold specified by the `RUN_DURATION_SECONDS` metric in the `health` block.
+* `on_streaming_backlog_exceeded` - (Optional) (List) list of notification IDs to call when any streaming backlog thresholds are exceeded for any stream.
 
 Note that the `id` is not to be confused with the name of the alert destination. The `id` can be retrieved through the API or the URL of Databricks UI `https://<workspace host>/sql/destinations/<notification id>?o=<workspace id>`
 

jobs/resource_job.go

@@ -170,17 +170,13 @@ func sortWebhookNotifications(wn *jobs.WebhookNotifications) {
 		return
 	}
 
-	notifs := [][]jobs.Webhook{wn.OnStart, wn.OnFailure, wn.OnSuccess}
+	notifs := [][]jobs.Webhook{wn.OnStart, wn.OnFailure, wn.OnSuccess,
+		wn.OnDurationWarningThresholdExceeded, wn.OnStreamingBacklogExceeded}
 	for _, ns := range notifs {
 		sort.Slice(ns, func(i, j int) bool {
 			return ns[i].Id < ns[j].Id
 		})
 	}
-
-	sort.Slice(wn.OnDurationWarningThresholdExceeded, func(i, j int) bool {
-		return wn.OnDurationWarningThresholdExceeded[i].Id < wn.OnDurationWarningThresholdExceeded[j].Id
-	})
-
 }
 
 // CronSchedule contains the information for the quartz cron expression
@@ -908,7 +904,8 @@ func gitSourceSchema(s map[string]*schema.Schema, prefix string) {
 }
 
 func fixWebhookNotifications(s map[string]*schema.Schema) {
-	for _, n := range []string{"on_start", "on_failure", "on_success", "on_duration_warning_threshold_exceeded"} {
+	for _, n := range []string{"on_start", "on_failure", "on_success",
+		"on_duration_warning_threshold_exceeded", "on_streaming_backlog_exceeded"} {
 		common.MustSchemaPath(s, "webhook_notifications", n).DiffSuppressFunc = nil
 	}
 }