Remove access to the clipboard from the Paste Global Transform operator poll function, as it can cause slowdowns when there is a lot of data on the clipboard. This also means that the parsing code has to be a bit more lenient to the contents of the clipboard. And, because the error message that there is no matrix on the clipboard is now going to be shown more often, I made it a bit more friendly. Pull Request: https://projects.blender.org/blender/blender/pulls/147562