Incompatibility with Solang-Polkadot Compiled Contracts

[tareknaser]

The current situation is that solang-aqd uses the unreleased version 5 of the metadata format, which contains breaking changes. Solang contracts are constructed with version 4 of ink_metadata, lacking the staticBufferSize field in the metadata. As the latest released version used by Solang is 4.3.0, it doesn't include this field yet.

To resolve this, an upgrade of Solang to use the yet unreleased version 5 of ink_metadata is suggested.
This upgrade will align the metadata structure and resolve the incompatibility with Solang-Polkadot compiled contracts.

This is also because we are using the yet unreleased version of contract-extrinsics crate (See #3)