Qt: Add patching errors

include/panda_qt/patch_window.hpp

@@ -1,5 +1,6 @@
 #pragma once
 #include <QLabel>
+#include <QMessageBox>
 #include <QWidget>
 #include <filesystem>
 
@@ -13,6 +14,15 @@ class PatchWindow final : public QWidget {
 	~PatchWindow() = default;
 
   private:
+	// Show a message box
+	// Title: Title of the message box to display
+	// Message: Message to display
+	// Icon: The type of icon (error, warning, information, etc) to display
+	// IconPath: If non-null, then a path to an icon in our assets to display on the OK button
+	void displayMessage(
+		const QString& title, const QString& message, QMessageBox::Icon icon = QMessageBox::Icon::Warning, const char* iconPath = nullptr
+	);
+
 	std::filesystem::path inputPath = "";
 	std::filesystem::path patchPath = "";