Frame: Give Referendum SubmitOrigin argument (#14326)

* Referedum's SubmitOrigin should have an arg

* Fixes

* Nits and two extra utils

* Fixes

* Fixes

substrate/frame/support/src/dispatch.rs

@@ -89,6 +89,26 @@ impl<AccountId> From<Option<AccountId>> for RawOrigin<AccountId> {
 	}
 }
 
+impl<AccountId> RawOrigin<AccountId> {
+	/// Returns `Some` with a reference to the `AccountId` if `self` is `Signed`, `None` otherwise.
+	pub fn as_signed(&self) -> Option<&AccountId> {
+		match &self {
+			Self::Signed(x) => Some(x),
+			_ => None,
+		}
+	}
+
+	/// Returns `true` if `self` is `Root`, `None` otherwise.
+	pub fn is_root(&self) -> bool {
+		matches!(&self, Self::Root)
+	}
+
+	/// Returns `true` if `self` is `None`, `None` otherwise.
+	pub fn is_none(&self) -> bool {
+		matches!(&self, Self::None)
+	}
+}
+
 /// A type that can be used as a parameter in a dispatchable function.
 ///
 /// When using `decl_module` all arguments for call functions must implement this trait.