Adapt to EIP-1193 provider changes

[mcmire]

After SafeEventEmitterProvider is updated to support EIP-1193 and a new version of @metamask/eth-json-rpc-provider is released, we should adapt to the changes:

• We should bump @metamask/eth-json-rpc-provider to rely on the new changes.
• At that point, calling sendAsync will be deprecated; we should use request instead.
  • There are only a couple places in the implementation where we are using sendAsync.
  • However, there are ~20 references in the tests. In particular, the tests make use of a provider whose sendAsync method is mocked. We need to update the helper code to mock request instead.