update integration heartbeat description to use 'alert group' instead of 'incident' (#1576)

## Which issue(s) this PR fixes
![Screenshot 2023-03-20 at 12 05
32](https://user-images.githubusercontent.com/9406895/226321853-05450b0a-c6f2-4558-8d84-757c9c40c24b.png)

## Checklist

- [ ] Tests updated (N/A)
- [ ] Documentation added (N/A)
- [x] `CHANGELOG.md` updated

CHANGELOG.md

@@ -14,7 +14,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
-- Updated wording in some Slack messages to use 'Alert Group' instead of 'Incident' ([1565](https://github.com/grafana/oncall/pull/1565))
+- Updated wording throughout plugin to use 'Alert Group' instead of 'Incident' ([1565](https://github.com/grafana/oncall/pull/1565),
+  [1576](https://github.com/grafana/oncall/pull/1576))
 
 ### Fixed
 

grafana-plugin/src/containers/HeartbeatModal/HeartbeatForm.tsx

@@ -85,11 +85,11 @@ const HeartbeatForm = observer(({ alertReceveChannelId, onUpdate }: HeartBeatMod
       <br />
       <br />
       <p>
-        A heartbeat acts as a healthcheck for incident monitoring. You can configure OnCall to regularly send alerts to
-        the heartbeat endpoint. If you don't receive one of these alerts, OnCall will issue an incident.
+        A heartbeat acts as a healthcheck for alert group monitoring. You can configure OnCall to regularly send alerts
+        to the heartbeat endpoint. If you don't receive one of these alerts, OnCall will issue an alert group.
       </p>
       <p>
-        <span>OnCall will issue an incident if no alert is received every</span>
+        <span>OnCall will issue an alert group if no alert is received every</span>
         <WithPermissionControlTooltip userAction={UserActions.IntegrationsWrite}>
           <Select
             className={cx('select', 'timeout')}