Fix crash when resizing container hidden in the scratchpad

Firstly, the container was wrongly identifying as a tiling container
because it had no workspace.

Secondly, when calculating the maximum possible size we can't use the
workspace if it's not there, so we'll allow unlimited size in this case.

sway/commands/resize.c

@@ -94,7 +94,7 @@ static void calculate_constraints(int *min_width, int *max_width,
 		*min_height = config->floating_minimum_height;
 	}
 
-	if (config->floating_maximum_width == -1) { // no maximum
+	if (config->floating_maximum_width == -1 || !con->workspace) { // no max
 		*max_width = INT_MAX;
 	} else if (config->floating_maximum_width == 0) { // automatic
 		*max_width = con->workspace->width;
@@ -102,7 +102,7 @@ static void calculate_constraints(int *min_width, int *max_width,
 		*max_width = config->floating_maximum_width;
 	}
 
-	if (config->floating_maximum_height == -1) { // no maximum
+	if (config->floating_maximum_height == -1 || !con->workspace) { // no max
 		*max_height = INT_MAX;
 	} else if (config->floating_maximum_height == 0) { // automatic
 		*max_height = con->workspace->height;

sway/tree/container.c

@@ -727,8 +727,14 @@ void container_set_geometry_from_floating_view(struct sway_container *con) {
 }
 
 bool container_is_floating(struct sway_container *container) {
-	return !container->parent && container->workspace &&
-		list_find(container->workspace->floating, container) != -1;
+	if (!container->parent && container->workspace &&
+			list_find(container->workspace->floating, container) != -1) {
+		return true;
+	}
+	if (container->scratchpad) {
+		return true;
+	}
+	return false;
 }
 
 void container_get_box(struct sway_container *container, struct wlr_box *box) {