[APM] Improve error message on Service Overview Page

[sorenlouv]

To use APM app the user needs to have read permissions to apm-* indices and general access to the APM app.
If the user lacks read permissions to apm-* they'll currently see an error toast but nothing that helps them understand what went wrong.

Solution
Let the user know which permissions they lack, and how they can get them. Perhaps with a screenshot or gif of the User Management screen and/or a direct link to User Management (although the user in question probably does not have permissions to give themselves access - the link it might still useful so they know where to point someone else).

[elasticmachine]

Pinging @elastic/apm-ui (Team:apm)

[formgeist]

@sqren I already opened #50052 - does that cover the same thing?

[sorenlouv]

I thought I saw this somewhere but didn't see it on our board. Should've looked in design. Closing.