Fleet Mode: Tooltip for the status pill

### Description

In #3287 we introduced "fleet mode" as the terminology to refer to a device not in developer mode.


The phrase "fleet mode" itself doesn't necessarily explain what this means, and @joepavitt and I would like to add a tooltip, but we're struggling to find a succint summary that isn't "developer mode: disabled".

Opening this issue for input from @MarianRaphael, @Steve-Mcl, @joepavitt and myself.

### Epic/Story

#3005

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate