Adds ability to trigger tasks via unsigned transactions

prdoc/pr_4075.prdoc

@@ -0,0 +1,14 @@
+title: Adds ability to trigger tasks via unsigned transactions
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      This PR updates the `validate_unsigned` hook for `frame_system` to allow valid tasks 
+      to be submitted as unsigned transactions. It also updates the task example to be able to 
+      submit such transactions via an off-chain worker.
+
+crates:
+  - name: frame-system
+    bump: patch
+  - name: pallet-example-tasks
+    bump: minor

substrate/frame/system/src/lib.rs

@@ -742,8 +742,6 @@ pub mod pallet {
 		#[pallet::call_index(8)]
 		#[pallet::weight(task.weight())]
 		pub fn do_task(origin: OriginFor<T>, task: T::RuntimeTask) -> DispatchResultWithPostInfo {
-			ensure_signed(origin)?;
-
 			if !task.is_valid() {
 				return Err(Error::<T>::InvalidTask.into())
 			}