When the QMenu is closed or the Purpose job finishes, we make sure to send a reply out and reset the pending reply serial.
However, when we determined on the host side that we cannot share the contents, we send a reply but don't reset the pending reply serial, having every subsequent purpose request fail until reloading the extension or restarting the browser.

5.17

(patched out the "isTrusted" check for testing)

• called navigator.share({title: "test"})
• then called navigator.share({url: "test})

Previously, the url request would fail as the title request (which is valid as far as canShare is concerned in the extension but not for Purpose on the host side) got rejected but not properly reset.
With this patch the url request opens purpose menu as expected