Allow RequestState.abort to be used with on modifier

[gitKrystan]

Description

Fixes the following error encountered when using state.abort (yielded by the Request component) with the on modifier:

util.js:579 Uncaught Error: You accessed `this._future` from a function passed to the `on` modifier, but the function itself was not bound to a valid `this` context. Consider updating to use a bound function (for instance, use an arrow function, `() => {}`).
    at assertOnProperty (util.js:579:1)
    at Object.get (util.js:583:1)
    at Proxy.abort (index.js:30:1364)

Notes for the release