servicemanager: remove TODO to combine sid checks

getDeclaredInstances in servicemanager does multiple security checks.
This is because someone may be asking about 'IFoo', and a client may
only have permissions to see 'IFoo/default' even though 'IFoo/other' may
be registered.

The idea to combine these security checks would mean granting permission
to "IFoo/*". However, using regex for service contents would be quite a
bit of additional complexity, and using prefix matches would make all
other service contexts messy.

Bug: 169275998
Test: N/A
Change-Id: I8c00ecbb75e7b2f5ce50828b54d6e0a4ee9ff29f