Reland "Toolbar avatar label only shown by default only on unmanaged devices"

This is a reland of commit 3894df276830eb2a064bb5780225dcebd250e41c

Original change's description:
> Toolbar avatar label only shown by default only on unmanaged devices
>
> By default the label is shown on managed profiles on unmanaged devices.
> If enabled explicitly by policy, the label will be shown on managed
> devices.
>
> Bug: b:322796016
> Change-Id: I6adbb43ea063e9e9d40470113a88c7135e63185d
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5362735
> Reviewed-by: Ryan Sultanem <rsult@google.com>
> Commit-Queue: Yann Dago <ydago@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1272307}

Bug: b:322796016
Change-Id: Iedd16081bc06481212380a3abf02c652c39b86c3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5366771
Reviewed-by: David Roger <droger@chromium.org>
Commit-Queue: Yann Dago <ydago@chromium.org>
Auto-Submit: Yann Dago <ydago@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1272883}