NIT PICKS ociocheck: Empty namespace for Interop ID? Warning message too strong when a valid Interop ID is used with a namespace ?

Whilst investigating the unused variable [here](https://github.com/AcademySoftwareFoundation/OpenColorIO/blob/main/src/apps/ociocheck/main.cpp#L90) I had some questions:

1. I wondered what it should do if the namespace is empty? (If the string begins with a ':')

2. I note that ociocheck will warn if a namespaced ID has the same spelling as an official ID - all good but do we feel the word 'must' is a little strong here? I know we are not a "Standard" body, but I'm imagining a world where a pre-official ID is being migrated to an official one and a user of ociocheck now thinks the file is in error. We'd obviously want users to migrate to an official one so maybe switch to 'should' ?

Start with src/apps/ociocheck/main.cpp around line 90 and trace how Interop IDs and namespaces are checked. Confirm the expected behavior for an ID beginning with ':' and the intended strength of the warning when a namespaced ID matches an official ID. Done means the behavior and wording are settled and covered by the relevant ociocheck checks.

Written by the indexing model from the issue text.