Lens "Add to dashboard" is appearing for underprivileged users

[legrego]

Kibana version: 7.11

Describe the bug:

Lens has a new "Save to dashboard" feature, which allows a Lens user to save their visualization within either a new or existing dashboard.

This display of this feature is not respecting the current user's privileges, so it give users an option that will ultimately fail.

Steps to reproduce:

1. Create a role which grants All access to Visualize, but no access to Dashboards
2. Create a user, and assign this role to them.
3. Login as the user created in step 2, and navigate to Lens
4. Create a new Lens visualization, and click Save.

Expected behavior:

A user without write access to Dashboards should not be given the option to create/modify them via this save dialog

Screenshots (if relevant):

[elasticmachine]

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

[poffdeluxe]

I spoke with @ryankeairns today about what the fix for this should look like. If the user is missing create new dashboard privileges, don't show the add to new dashboard option. If the user is missing edit privileges, don't show the add to existing dashboard option. If the user is neither or doesn't not have any dashboard access, then don't show the "add to dashboard" options and default to add to library.

I'm going to wait to fix this until @clintandrewhall's PR here is merged: #88112
The reason being is so it'll be easy to grab capabilities of the logged in user from within the plugin rather than having the consuming application be responsible for passing in the user's capabilities.

[nreese]

@poffdeluxe will maps be impacted by this once #88759 is merged? Will maps have to do anything or will SavedObjectSaveModalDashboard handle the details internally?

[flash1293]

Removing Lens tag as this looks like a general issue. Please add back if I'm mistaken

[poffdeluxe]

@nreese Apologies for the late reply here but the modal will handle it internally. @clintandrewhall's PR here includes a first pass at handling some of the privileges. So, all that being said, no changes will have to be made specifically to maps.

[poffdeluxe]

Fixed as a small part of #88112

[poffdeluxe]

With a test for it here: #89245

[legrego]

🎉 Thanks, team!