Improve Dispatch Errors (#878)

* better dispatch errors

* dry_run to use same DispatchError

* fix dry_run_fails; use correct transfer amount

* Hide ModuleError impl and avoid pulling details from metadata unless user needs them

* fix tests

* actually fix the tests (hopefully..)

* Add a couple more DispatchError test cases

* Add a comment about where the error was copied from

* Also expose a way to obtain the raw module error data

* Remove redundant variant prefixes

* explicit lifetime on From<str> for clarity

* fmt

subxt/src/tx/tx_progress.rs

@@ -324,7 +324,7 @@ impl<T: Config, C: OnlineClientT<T>> TxInBlock<T, C> {
             let ev = ev?;
             if ev.pallet_name() == "System" && ev.variant_name() == "ExtrinsicFailed" {
                 let dispatch_error =
-                    DispatchError::decode_from(ev.field_bytes(), &self.client.metadata());
+                    DispatchError::decode_from(ev.field_bytes(), self.client.metadata())?;
                 return Err(dispatch_error.into());
             }
         }
@@ -344,7 +344,7 @@ impl<T: Config, C: OnlineClientT<T>> TxInBlock<T, C> {
             .rpc()
             .block(Some(self.block_hash))
             .await?
-            .ok_or(Error::Transaction(TransactionError::BlockHashNotFound))?;
+            .ok_or(Error::Transaction(TransactionError::BlockNotFound))?;
 
         let extrinsic_idx = block
             .block
@@ -357,7 +357,7 @@ impl<T: Config, C: OnlineClientT<T>> TxInBlock<T, C> {
             })
             // If we successfully obtain the block hash we think contains our
             // extrinsic, the extrinsic should be in there somewhere..
-            .ok_or(Error::Transaction(TransactionError::BlockHashNotFound))?;
+            .ok_or(Error::Transaction(TransactionError::BlockNotFound))?;
 
         let events = EventsClient::new(self.client.clone())
             .at(Some(self.block_hash))