sway/commands: Handle incorrect resize unit

problem: an invalid usage of the command resize set will cause sway to crash because it doesn't check for an invalid height.
solution: validate height along with width.

sway/commands/resize.c

@@ -457,7 +457,7 @@ static struct cmd_results *cmd_resize_set(int argc, char **argv) {
 		if (argc > num_consumed_args) {
 			return cmd_results_new(CMD_INVALID, "%s", usage);
 		}
-		if (width.unit == MOVEMENT_UNIT_INVALID) {
+		if (height.unit == MOVEMENT_UNIT_INVALID) {
 			return cmd_results_new(CMD_INVALID, "%s", usage);
 		}
 	}