Hide eject icon of removable media on the root list of Files app when
primary shared storage is in adopted media due to the following reasons.
- Primary shared storage should not be easily ejected because that
causes the situation that there's no primary shared storage
- To align with the Storage settings (Settings > Storage), eject icon
is disabled in this menu when the removable media is adopted
- Eject action from Files app can only unmount primary shared storage
Bug: 117252468
Test: manual
Change-Id: Idd76229fb10db621a817afd60295787c761345b1
f5f03fc083