Fixed Edit trade platforms selected incorrectly

1) Create trade with PC (possibly others, only coincidentally tested with PC as that's the only platform I used)
2) Edit trade (just wanted to remove region selection)

Result:
When editing, the Switch platform button is also selected (in addition to the actually selected PC). Saving without touching that button does not add the Switch as a platform, despite the button being toggled on. De-selecting and then re-selecting before the save does add Switch.
So basically, incorrect button toggle state shown when opening edit but not affecting the saved filters if ignored.