[ObxUx][Infra] Alerts section: show alerts count and close the section if there are no alerts

[jennypavlova]

Follow up: #175558

Summary

In this issue, we should Investigate a way to get the alerts to count from the alerts widget and show it in the alerts section (some ideas around onLoaded returning the alerts count information).
The idea is to show a message (f.e. No active alerts found) in case there are no active alerts and close the alerts section by default. If there are active alerts we should show the alerts section in an open state:

• No active alerts (default state):
  
• Active alerts (default state):
  

Technical details

Currently, inside the AlertSummaryWidget we don't have a way to get the alerts count (We can get them using the useAlertsCount hook but then we will make another HTTP request which we are trying to avoid) Part of the investigation here will include getting the alerts count from the widget and use it in the alerts section (Check if onLoaded can provide it as suggested).

More background details in the discussion and this draft PR's commit
The flow:

Screen.Recording.2024-01-31.at.17.56.19.mov

1 - Open the flyout
2 - The alert widget starts to load - the alerts section is open at this point.
3 - When the widget finishes loading, we will have a callback for the onLoaded that will control the open/closed state based on the counter.
4 - Collapse or keep the section expanded

❓ For the closed section when there are alerts we can still show how many alerts are available in addition to getting closer to the idea in the epic

Investigate whether the AlertSummaryWidget can provide the counter information via an event handler after the component has loaded

AC

• When the user opens the hosts details (flyout page):
  • Host with no active alerts: the alerts section should be closed by default showing a message (f.e. No active alerts found)
  • Host with active alerts: the alerts section should be open by default (showing section content)
    • An addition can be to show the active alerts count when the section is closed (next to the title)