fdo#45962: fix context menu key yanking cursor out of header/footer
For the "context menu" key VCL synthesizes a cursor position that is the
center of the window, hence likely to be in the document body.
When SwEditWin::Command calls lcl_CheckHeaderFooterClick, it then moves
the document view cursor; prevent that by only calling that for actual
mouse events. (regression from
a6176612ff1a6a142a68964b2c0834d28125fc45)
(cherry picked from commit
87279e0e812bac7f2c17f2758a39bcfd942214af)
Signed-off-by: Miklos Vajna <vmiklos@suse.cz>