Exit with remaining text if user touches outside dialog

[AbdullahM0hamed]

Closes #275.

Chose to exit with text instead of keeping the dialog, because https://github.com/termux/termux-api/blob/67954de3638b45abed48c40b4df907ebd940ee32/app/src/main/java/com/termux/api/DialogActivity.java#L989 indicates that that's intended behaviour.