Underpriced speed-up can cause confusing error state

[danfinlay]

Steps to reproduce:

1. Submit a tx at a low gas price
2. Click "speed up" on the tx
3. Select the "slow" gas price of the available options.

Result:

• The RPC returned an error with the message "replacement transaction underpriced"
• This transitions the replacement tx to a "failed" state.
• The transaction history now shows "failed", implying to the user this tx has failed (this failure is indistinguishable from an on-chain failure), even though there is still a valid "submitted" transaction before that failed one.
• Upon retrying, the new transaction has the NEXT nonce (probably because of the valid "submitted" one with the lower nonce).

Expected result:

• Ideally, the user is not shown gas options that will result in "tx underpriced" errors.
• If a speed up attempt does fail with an RPC error, the user should stay on the confirmation screen, be shown this as an error, and have a chance to select a new gas price.

[tmashuang]

Related to #9053

[tmashuang]

For testing purposes, on a Test Network we can take advantage of the exceeds block gas limit error from the RPC to simulate the tx failure.

1. Submit a tx on a testnet (Rinkeby) with a gas price < 1
2. Click Speed Up
3. Under Advanced Tab for gas limit set to 10000000000 . Gas price to 1 , this shouldn't matter though.
4. Click the Save button

This will/should update the tx list item to a failed state. Thus not showing any visible indication of the tx with gas price < 1 that has been submitted, and still pending on the network. I think this is fundamental issue on how we present transactions in the transaction list which #9041 is suppose to patch, not entirely fix.