fix: propagate GraphQL errors from updateRecipientPreferences (SUP-561)

[mikemilla]

Summary

• client-graphql: updateRecipientPreferences now checks results.error from the GraphQL mutation and throws instead of silently swallowing errors.
• react-hooks: Added UPDATE_RECIPIENT_PREFERENCES/ERROR case to the preferences reducer, which clears isUpdating and surfaces the error in state. Added error field to PreferenceState type.
• Companion to backend fix: https://github.com/trycourier/backend/pull/9319

Test plan

• Verify existing preference update flows still work (status, routing, digest schedule)
• Verify that a backend GraphQL error now surfaces in the SDK instead of being silently ignored
• Verify isUpdating resets to false on error

Made with Cursor

[linear]

SUP-561 G3 - updateRecipientPreferences Returns `null` Without Updating