Previously, some settings migrations only operated on root-level keys
and missed settings nested under platform keys (`macos`, `linux`, etc.),
channel keys (`nightly`, `stable`, etc.), or profile blocks. This fixes
migrations to recurse into those nested locations.
Also fixes `m_2026_02_02` to gracefully skip when `edit_predictions` is
not an object (e.g. `true`) instead of bailing and aborting the entire
migration chain.
Release Notes:
- Fixed settings migrations to correctly handle settings nested under
platform, channel, or profile keys.