Consider splitting get_associated_ruff_rules into two cases for managed and non-managed rules

[nathanjmcdougall]

Motivation
Not all rules are managed, e.g. INP for import-linter. At the moment, it is tool-dependent whether the rules from get_associated_ruff_rules are managed. We should probably make this distinction explicit in the interface

Summary of desired enhancement
Introduce a new method to distinguish managed vs. non-managed ruff rules associated with a tool.

[nathanjmcdougall]

We have our is_managed_rule method etc. so we need to be careful here. It might be we just approach this in a simpler way where we use that other method, but the general idea holds.

[nathanjmcdougall]

We should add INP for import-linter once this is available.

[nathanjmcdougall]

I don't think this is urgent enough to be in the next milestone.

[nathanjmcdougall]

Will resolve in a slightly different way via #563.