lisp/org-colview.el: Update org-columns to respect global-visual-line-mode
* lisp/org-colview.el (org-columns): Prevent enabling `truncate-lines'
when `global-visual-line-mode' is enabled.
This fixes a bug where `org-columns' overlays were disabling wrapping
of lines when `global-visual-line-mode` was already activated, and so
therefore expectation was that the lines would continue wrapping.
This is because `org-columns' was setting truncate-lines to t, when
global-visual-line-mode requires it to be set to nil. The interaction
between the two caused the wrapping not to occur.