patch 8.2.4328: command line complete matches cleard when typing character

Problem:    Command line complete matches cleard when typing character.
            (Dominique Pellé)
Solution:   Only remove a popup menu if there is one.
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 5def8a6..63f1c5d 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -1883,7 +1883,8 @@
 		&& c != Ctrl_L)
 	{
 #ifdef FEAT_WILDMENU
-	    cmdline_pum_remove();
+	    if (cmdline_pum_active())
+		cmdline_pum_remove();
 #endif
 	    (void)ExpandOne(&xpc, NULL, NULL, 0, WILD_FREE);
 	    did_wild_list = FALSE;