ComponentAlias: Change device config namespace

Now use the namespace "activity_manager_ca".

Reason: When the device boots up, phenotype will reset all the values
in "activity_manager". To avoid it, we use a different namespace.

Test: atest ComponentAliasTests ComponentAliasTests1 ComponentAliasTests2
Bug: 196254758

Change-Id: I540417a1e1b612424e8426981c1e02e1c68132f8