Don't assert the cursor theme loads

If it doesn't load, it's a runtime error, so we shouldn't use an
assertion.

sway/input/seat.c

@@ -914,8 +914,10 @@ void seat_configure_xcursor(struct sway_seat *seat) {
 		wlr_xcursor_manager_destroy(seat->cursor->xcursor_manager);
 		seat->cursor->xcursor_manager =
 			wlr_xcursor_manager_create(cursor_theme, cursor_size);
-		sway_assert(seat->cursor->xcursor_manager,
+		if (!seat->cursor->xcursor_manager) {
-					"Cannot create XCursor manager for theme");
+			sway_log(SWAY_ERROR,
+				"Cannot create XCursor manager for theme '%s'", cursor_theme);
+		}
 	}
 
 	for (int i = 0; i < root->outputs->length; ++i) {
@@ -924,11 +926,11 @@ void seat_configure_xcursor(struct sway_seat *seat) {
 		bool result =
 			wlr_xcursor_manager_load(seat->cursor->xcursor_manager,
 				output->scale);
-
+		if (!result) {
-		sway_assert(!result,
+			sway_log(SWAY_ERROR,
 				"Cannot load xcursor theme for output '%s' with scale %f",
-			// TODO: Fractional scaling
+				output->name, output->scale);
-			output->name, (double)output->scale);
+		}
 	}
 
 	cursor_set_image(seat->cursor, "left_ptr", NULL);