contracts: Change define_env! to expect a Result<T, DispatchError> for every function (#7762)

* Make host functions return TrapReason

This avoids the need to manually store any trap reasons
to the `Runtime` from the host function. This adds the following
benefits:

* It properly composes with the upcoming chain extensions
* Missing to set a trap value is now a compile error

* review: Remove superflous .into()

substrate/frame/contracts/src/wasm/mod.rs

@@ -1537,7 +1537,7 @@ mod tests {
 				&mut gas_meter
 			),
 			Err(ExecError {
-				error: Error::<Test>::ContractTrapped.into(),
+				error: Error::<Test>::TooManyTopics.into(),
 				origin: ErrorOrigin::Caller,
 			})
 		);
@@ -1582,7 +1582,7 @@ mod tests {
 				&mut gas_meter
 			),
 			Err(ExecError {
-				error: Error::<Test>::ContractTrapped.into(),
+				error: Error::<Test>::DuplicateTopics.into(),
 				origin: ErrorOrigin::Caller,
 			})
 		);