Ensure that users can read the error message RPC error messages that result upon attempting to submit a transaction

JSON-RPC error issue raised by Optimism.

- Metamask chrome extension does not surface RPC methods to users, it just reverts.
- When we reject transactions for paying either too much or not high enough of a fee, we reject it at the RPC level and return an informative error message. Whenever this happens in the MM chrome extension right now, the error message is displayed for a fraction of a second and then transaction just appears as failed. It would be ideal if we could surface this error message to users.

https://user-images.githubusercontent.com/6951929/123484628-ab625d00-d5d6-11eb-9e1b-7de9dc102157.mov

Start by tracing transaction submission in the MetaMask Chrome extension and how JSON-RPC errors are passed to the transaction status UI. Reproduce a fee-rejection transaction using the linked recording as context, then verify that the informative RPC error remains visible long enough for the user to read it instead of only showing a failed transaction.

Written by the indexing model from the issue text.