Add library remains open for users to add panels on dashboards when they are not in edit dashboard

[bhavyarm]

Kibana version: 7.11.0 BC1

Elasticsearch version: 7.11.0 BC1

Server OS version: darwin_x86_64

Browser version: chrome latest

Browser OS version: OS X

Original install method (e.g. download page, yum, from source, etc.): from staging

Describe the bug: This is a fun bug. If user clicks on share option(for ex: for printing reports) on dashboard when add library is still open (you are editing a dashboard) - Kibana tells the user to save the dashboard as expected. Once user saves the dashboard - you can still add panels because add library panel is open and you can navigate away from this dashboard and Kibana doesn't tell the user that their changes are going to be lost.

Steps to reproduce:

1. While editing a dashboard (which has been previously saved) - open add library panel and then click on share
2. Kibana tells the user to save the dashboard - save the dashboard while add library panel is still open
3. You can keep adding objects from the add library panel now that you are in view dashboard mode (not in edit mode anymore)
4. You can also navigate away from the dashboard after adding a bunch of stuff and there is no warning from Kibana to tell the user don't do it.

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[ThomThomson]

This is a funny issue - most likely caused by #82909 I am looking into a fix. Just confirmed that this happens in 7.10.1 as well.

When you follow the steps with a dashboard that has not been previously saved, the toast success message for adding a panel comes up, but no panels are actually added.

The most likely fix would be to close the add panel if it's open on save. I will see if that's possible. If so, it should probably be backported into 7.11.0 as well as 7.10.2