Fix crash on quickly switching workspaces

The hyprland/window widget had an assertion ensuring that the output
from hyprctl matched the currently selected workspace id. However this
assertion fails if workspaces are switched too quickly, causing the
selected workspace to differ in id from the one in hyprctl, failing this
assertion which then crashes the entire program.

This fix simply changes this assertion into an if statement, and if a
mismatch is found, empty string is returned as the window name.

src/modules/hyprland/window.cpp

@@ -59,7 +59,10 @@ std::string Window::getLastWindowTitle(uint workspaceID) {
   auto workspace = std::find_if(json.begin(), json.end(), [&](Json::Value workspace) {
     return workspace["id"].as<uint>() == workspaceID;
   });
-  assert(workspace != std::end(json));
+
+  if (workspace != std::end(json)) {
+    return "";
+  }
   return (*workspace)["lastwindowtitle"].as<std::string>();
 }