Document Manager; Dragging files to Logs and Files grids now works slightly differently

Previously, dragging a file from Windows Explorer to a Logs grid (e.g., on the Accounts form, Logs page) worked slightly differently to dragging the file onto the Files grid (on the Files page).

When dragging to the Logs grid, a new Log would be created, even if the User chose to overwrite the existing file.

With this change, various messages have been improved and some now have the ability to be cancelled.

Also, if a file is dragged to the Logs grid and the User chooses to overwrite the file, a new Log will NOT be created unless the file has been dragged over an existing Log and the User has already chosen to continue a conversation thread.