[Browser plugin connector] Implement missing signing methods

[alexjba]

Description

https://docs.metamask.io/wallet/concepts/signing-methods/

Methods needed:

• eth_signTypedData_v4
• eth_signTypedData - deprecated
• eth_signTransaction
• eth_sign - deprecated

https://www.notion.so/Bring-Browser-Connect-to-the-Same-Level-as-Wallet-Connect-c1f5860267df458580d9fe03d659103b

[alexjba]

These methods are reported as being deprecated by Metamask. https://docs.metamask.io/wallet/concepts/signing-methods/#deprecated-signing-methods
Need to analyze if the connector should implement these methods or not

eth_signTypedData
eth_sign

cc @alaibe @saledjenic

[alexjba]

The deprecated methods won't be implemented

[alexjba]

eth_signTransaction is not yet supported by WC. We'll need to implement for both integrators if needed

[alexjba]

@saledjenic @alaibe Need some help to determine if this is a must for 2.32, for WC and BC!

My oppinion here is that it's not a must. Currently I don't see a clear real life use case and for this and can't find a dApp or a dApp feature that requires eth_signTransaction . We've had it implemented in the initial version for WC, but was removed for the same reason: There was no clear real life dapp use case: #15661