[Spending limits] Non-owners with a spending limit allowance cannot interact with the Safe

[katspaugh]

Bug description

It's possible to add spending limits to any Ethereum address, even non-owners. However, the UI still shows that Safe as "read-only" for such users.

Environment

• Browser: Chrome
• Wallet: MetaMask
• Chain: Ethereum mainnet

Steps to reproduce

1. Add a spending limit to a non-owner
2. Try to make a transaction (bummer!)

[iamacook]

For reference, a delegate management PoC was worked on in the past here (though safe-react-based) and I prepared the types for the delegate endpoints for it as well.

[katspaugh]

It might be not necessary to delegate, @francovenica says it's possible to create these transactions on the contract level.