Clicking refresh on iFrame after few user actions gives access to whole of Kibana

[bhavyarm]

Kibana version: 7.11.0 BC4

Elasticsearch version: 7.11.0 BC4

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: If user clicks on refresh on iframe after performing a few actions - they have access to whole of Kibana not just iFrame.

Steps to reproduce:

1. Open an iFrame(I made an iFrame of an dashboard with top nav menu bar included) containing html in a browser - login if you have to - iframe gets displayed correctly
2. Click on edit on iFrame and click on create panel and then click cancel on new panel window
3. There is a discard changes message? ->click yes and then iFrame gets displayed without the top nav menu bar
4. Click refresh - now you have access to other parts of Kibana- not just the iFrame

Screenshots (if relevant):

[elasticmachine]

Pinging @elastic/kibana-app-services (Team:AppServices)

[elasticmachine]

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

[lizozom]

It seems to me that this is related to how Dashboard behaves, so I'm adding the @elastic/kibana-presentation team to evaluate this

[Dosant]

I am putting the blocked label because it seems it deserves a broader discussion and a somewhat generic approach as part of #93200 and also it isn't high impact.

[ThomThomson]

Closing this for the time being. It will be tracked in our Icebox for Iframe / Embedding issues and will be re-opened if our priorities change.