Revert "Reset the input prior to processing it in order to prevent issues with per...

Revert "Reset the input prior to processing it in order to prevent issues with per-chat history. fixes 984"

This reverts commit b56a8712f3063e93b68bfa6bd8f2ec67e955df50.

That solution had the side effect that the textEdit would already been cleared when the textEntered() signal
was sent out. This broke the assumption that consumers of that signal could access the edit's content.
We'll find a better solution for the history problems.