MIRTH-3089: Fixed bug that caused the channel "Allow message archiving" property to not work.
MIRTH-3089: Forgot to commit the changes to DataPrunerTest.
Fixed memory leak in Frame caused by the KeyboardFocusManager. Now we save a reference to the KeyEventDispatcher and remove it when logging out.

Removed unused instance of MessageExportDialog in the message browser.
Issue: MIRTH-3074
MIRTH-3089: Added a line to the PrunerTask constructor that was neglected before.