Update category for AccountDetailDashboardFragment.

- use a separate category key for AccountDetailDashboardFragment instead
of sharing the same key with UserAndAccountDashboardFragment. Tile using
the original category will now show up at the top level account
setting, and tile using the new account detail detail will be displayed
under the specified account type.

Bug: 62446202
Test: make RunSettingsRoboTests
Change-Id: I06f781a20f24498bdc6207aef5469be9cd0c8e47