input/cursor: reset event source after unhide

Reset the event source after unhiding the cursor, to ensure that the
timeout starts after showing the cursor. Also remove the open coded
variant in seat_consider_warp_to_focus().

Fixes #5679

sway/input/cursor.c

@@ -299,6 +299,7 @@ void cursor_unhide(struct sway_cursor *cursor) {
 		cursor_set_image(cursor, image, cursor->image_client);
 	}
 	cursor_rebase(cursor);
+	wl_event_source_timer_update(cursor->hide_source, cursor_get_timeout(cursor));
 }
 
 static void pointer_motion(struct sway_cursor *cursor, uint32_t time_msec,

sway/input/seat.c

@@ -1482,7 +1482,6 @@ void seat_consider_warp_to_focus(struct sway_seat *seat) {
 	}
 	if (seat->cursor->hidden){
 		cursor_unhide(seat->cursor);
-		wl_event_source_timer_update(seat->cursor->hide_source, cursor_get_timeout(seat->cursor));
 	}
 }