R1:bd0011076ba1

Don't disrupt repository import chain when publishing is disabled

Summary:
Fixes T4736. Currently, we incorrectly skip the `writeImportStatusFlag()` call if publishing is disabled (the `herald-disabled`) check. This means we don't flag the commit as imported, and don't move the pipeline forward correctly.

Instead, we only want to skip the owners stuff, not the pipeline stuff. Move that to a method.

(Also fix a nearby TODO now that we have a permanent failure exception.)

Test Plan:
- Used…