Better expect error messages (#2629)

* Replace expect error messages

* Change message

* Create RuntimeError struct

* Pass error through core methods

* Fix use of Runtime::current in signals package

* Fix tests

* Add #[track_caller] for better error output and fix maybe_with_rt

* provide a help message along with RuntimeError

---------

Co-authored-by: Evan Almloff <evanalmloff@gmail.com>

packages/core/src/generational_box.rs

@@ -91,6 +91,6 @@ pub fn current_owner<S: AnyStorage>() -> Owner<S> {
 impl ScopeId {
     /// Get the owner for the current scope.
     pub fn owner<S: AnyStorage>(self) -> Owner<S> {
-        Runtime::with_scope(self, |cx| cx.owner::<S>()).expect("to be in a dioxus runtime")
+        Runtime::with_scope(self, |cx| cx.owner::<S>()).unwrap()
     }
 }