Metadata V16: Implement support for Pallet View Functions (#1981)

* Support Pallet View Functions in Subxt

* fmt

* clippy

* Move a little view function logic to subxt_core

* clippy

* Add back check that prob isnt needed

* avoid vec macro in core

* Add view funciton test and apply various fixes to get it working

* Add test for dynamic view fn call and fix issues

* clippy

* fix test-runtime

* fmt

* remove export

* avoid vec for nostd core

* use const instead of fn for view fn call name

* Update to support latest unstable metadata

* Update metadata stripping tests for new v16 version

core/src/error.rs

@@ -105,6 +105,9 @@ pub enum MetadataError {
     /// Runtime method not found.
     #[error("Runtime method with name {0} not found")]
     RuntimeMethodNotFound(String),
+    /// View Function not found.
+    #[error("View Function with query ID {} not found", hex::encode(.0))]
+    ViewFunctionNotFound([u8; 32]),
     /// Call type not found in metadata.
     #[error("Call type not found in pallet with index {0}")]
     CallTypeNotFoundInPallet(u8),