sapphire-wagmi-v2: Add EIP-6963 support

[lubej]

SUMMARY

Current implementation of @oasisprotocol/sapphire-wagmi-v2 only supports default injected EIP-1193 provider:

Please note that while EIP-6963 (Multi Injected Provider Discovery) is supported by Wagmi it is only possible to wrap the default injected EIP-1193 compatible provider. For this reason you must disable MIPD support in the Wagmi configuration as additional discovered providers will not be Sapphire wrapped.

Currently setting to:

   {
      // ...
      multiInjectedProviderDiscovery: false,
      // ...
   }

Disables EIP-6963 functionality.

ISSUE TYPE

• Feature request

COMPONENT NAME

ADDITIONAL INFORMATION

Currently it is easy to misuse @oasisprotocol/sapphire-wagmi-v2. If you don't use EIP-1193 injected provider, and use one provided by EIP-6963, could result in provider not being correctly wrapped. Implementing EIP-6963 would result in clearer way of how to use @oasisprotocol/sapphire-wagmi-v2 and package not being misused.