Settings and inventory reliability fixes

A round of fixes to settings, inventory counts, and order handling.

• Fixed notification preferences flickering between on and off when switching Settings tabs.
• Moved receipt generation preferences (auto-generate, sound) out of the receipt screen and into Account settings.
• Fixed inventory on-hand counts double-subtracting sales for hosted organizations.
• Fixed the "Add a service" row overflowing its dialog on narrow screens.
• Orders can now be cancelled even when delivery confirmation keeps failing.