fix: Process.pid and Quickshell.env returning undefined instead of null

src/core/qmlglobal.cpp

@@ -79,7 +79,7 @@ void QuickshellGlobal::updateScreens() {
 
 QVariant QuickshellGlobal::env(const QString& variable) { // NOLINT
 	auto vstr = variable.toStdString();
-	if (!qEnvironmentVariableIsSet(vstr.data())) return QVariant();
+	if (!qEnvironmentVariableIsSet(vstr.data())) return QVariant::fromValue(nullptr);
 
 	return qEnvironmentVariable(vstr.data());
 }

src/io/process.cpp

@@ -20,7 +20,7 @@ void Process::setRunning(bool running) {
 }
 
 QVariant Process::pid() const {
-	if (this->process == nullptr) return QVariant();
+	if (this->process == nullptr) return QVariant::fromValue(nullptr);
 	return QVariant::fromValue(this->process->processId());
 }