Fix commandless tasks

Part of #76611

src/vs/workbench/contrib/tasks/browser/terminalTaskSystem.ts

@@ -471,7 +471,7 @@ export class TerminalTaskSystem implements ITaskSystem {
 		const resolvedVariables = this.resolveVariablesFromSet(this.currentTask.systemInfo, this.currentTask.workspaceFolder!, task, variables);
 
 		return resolvedVariables.then((resolvedVariables) => {
-			if (resolvedVariables && task.command && task.command.runtime) {
+			if (resolvedVariables && task.command && task.command.name && task.command.runtime) {
 				this.currentTask.resolvedVariables = resolvedVariables;
 				return this.executeInTerminal(task, trigger, new VariableResolver(this.currentTask.workspaceFolder!, this.currentTask.systemInfo, resolvedVariables.variables, this.configurationResolverService));
 			} else {