`ShorebirdUpdater.update()` previously threw `UpdateException: No update
(noUpdate)` whenever the patch check returned no available update, even
though that is a successful outcome of calling `update()` — the app is
already running the latest patch.
The wrapper only returned normally on `SHOREBIRD_UPDATE_INSTALLED`;
every other status (including `SHOREBIRD_NO_UPDATE`, value 0) fell
through to the generic `throw UpdateException(...)` path, which is
why callers saw `UpdateException: No update (noUpdate)` in their
exception telemetry.
Treat `SHOREBIRD_NO_UPDATE` as a successful return alongside
`SHOREBIRD_UPDATE_INSTALLED`. No FFI change, safe against any engine
version (status code 0 is stable).
Fixesshorebirdtech/shorebird#3681
Eric Seidel
b8987364e3