[Task Manager] Changed alerts schedule logic to use Task Manager internals

x-pack/plugins/alerts/server/alerts_client/alerts_client.ts

@@ -253,7 +253,11 @@ export class AlertsClient {
     if (data.enabled) {
       let scheduledTask;
       try {
-        scheduledTask = await this.scheduleAlert(createdAlert.id, rawAlert.alertTypeId);
+        scheduledTask = await this.scheduleAlert(
+          createdAlert.id,
+          rawAlert.alertTypeId,
+          data.schedule
+        );
       } catch (e) {
         // Cleanup data, something went wrong scheduling the task
         try {
@@ -697,7 +701,11 @@ export class AlertsClient {
         this.invalidateApiKey({ apiKey: updateAttributes.apiKey });
         throw e;
       }
-      const scheduledTask = await this.scheduleAlert(id, attributes.alertTypeId);
+      const scheduledTask = await this.scheduleAlert(
+        id,
+        attributes.alertTypeId,
+        attributes.schedule as IntervalSchedule
+      );
       await this.unsecuredSavedObjectsClient.update('alert', id, {
         scheduledTaskId: scheduledTask.id,
       });
@@ -933,9 +941,10 @@ export class AlertsClient {
     ]);
   }
 
-  private async scheduleAlert(id: string, alertTypeId: string) {
+  private async scheduleAlert(id: string, alertTypeId: string, schedule: IntervalSchedule) {
     return await this.taskManager.schedule({
       taskType: `alerting:${alertTypeId}`,
+      schedule,
       params: {
         alertId: id,
         spaceId: this.spaceId,

x-pack/plugins/alerts/server/alerts_client/tests/create.test.ts

@@ -353,6 +353,9 @@ describe('create()', () => {
                                                                               "alertId": "1",
                                                                               "spaceId": "default",
                                                                             },
+                                                                            "schedule": Object {
+                                                                              "interval": "10s",
+                                                                            },
                                                                             "scope": Array [
                                                                               "alerting",
                                                                             ],

x-pack/plugins/alerts/server/alerts_client/tests/enable.test.ts

@@ -201,6 +201,9 @@ describe('enable()', () => {
         alertId: '1',
         spaceId: 'default',
       },
+      schedule: {
+        interval: '10s',
+      },
       state: {
         alertInstances: {},
         alertTypeState: {},