Fixing issue which has crept to LIVE environment which resulted in the
clear input script not firing it's events

There was a change a few weeks ago to the DoughBaseComponents.js, in which
uiEvents were now taken from the config which is passed in when the component
is created. Clear input was not updated to follow this new convention
Altering clear input module to use keyup rather than keydown.

- When firing a keydown event the browser returns the value of the
  text box BEFORE the latest character is added.
- When clearing the text box, the X wasn't dissappearing because
  it was still returning the value of the text before it was cleared
- altering it to keyup will return the very latest value of the textbox
  fixing this issue
Merge pull request #774 from moneyadviceservice/clear_input_keyup

Altering clear input module to use keyup rather than keydown.