BREAKING - Try-runtime: Use proper error types (#13993)

* Try-state: DispatchResult as return type

* try_state for the rest of the pallets

* pre_upgrade

* post_upgrade

* try_runtime_upgrade

* fixes

* bags-list fix

* fix

* update test

* warning fix

* ...

* final fixes 🤞

* warning..

* frame-support

* warnings

* Update frame/staking/src/migrations.rs

Co-authored-by: Liam Aharon <liam.aharon@hotmail.com>

* fix

* fix warning

* nit fix

* merge fixes

* small fix

* should be good now

* missed these ones

* introduce TryRuntimeError and TryRuntimeResult

* fixes

* fix

* removed TryRuntimeResult & made some fixes

* fix testsg

* tests passing

* unnecessary imports

* Update frame/assets/src/migration.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

---------

Co-authored-by: Liam Aharon <liam.aharon@hotmail.com>
Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

substrate/frame/election-provider-support/src/lib.rs

@@ -189,6 +189,9 @@ pub use sp_npos_elections::{
 };
 pub use traits::NposSolution;
 
+#[cfg(feature = "try-runtime")]
+use sp_runtime::TryRuntimeError;
+
 // re-export for the solution macro, with the dependencies of the macro.
 #[doc(hidden)]
 pub use codec;
@@ -564,7 +567,7 @@ pub trait SortedListProvider<AccountId> {
 
 	/// Check internal state of the list. Only meant for debugging.
 	#[cfg(feature = "try-runtime")]
-	fn try_state() -> Result<(), &'static str>;
+	fn try_state() -> Result<(), TryRuntimeError>;
 
 	/// If `who` changes by the returned amount they are guaranteed to have a worst case change
 	/// in their list position.