Fix README after test module split

Recently we've split the CtsScopedStorageDeviceOnlyTest module into multiple ones.
CtsScopedStorageDeviceOnlyTest is still present, in addition to new modules.
So it should also be in Readme file.

Change-Id: I265ca2f702ed04a2f83ec127908372e52b09175d
Test: n/a
Bug: 294741813