Fix txpool transaction replacement

[l0r1s]

Fix the txpool by banning replacement transaction: opentensor/polkadot-sdk@df2f9b5...a584a57

Disabled by default and can be enabled by using SUBSTRATE_ALLOW_TX_REPLACEMENT=1

Test executed: https://gist.github.com/l0r1s/5c8d478f17125ba506c9d3879584e10b

[github-actions]

🚨🚨🚨 HOTFIX DETECTED 🚨🚨🚨

It looks like you are trying to merge a hotfix PR into main. If this isn't what you wanted to do, and you just wanted to make a regular PR, please close this PR, base your changes off the devnet-ready branch and open a new PR into devnet ready.

If you are trying to merge a hotfix PR, please complete the following essential steps:

1. go ahead and get this PR into main merged, so we can get the change in as quickly as possible!
2. merge main into testnet, bumping spec_version
3. deploy testnet
4. merge testnet into devnet, bumping spec_version
5. deploy devnet
6. merge devnet into devnet-ready

If you do not complete these steps, your hotfix may be inadvertently removed in the future when branches are promoted to main, so it is essential that you do so.

[camfairchild]

opentensor/frontier@f12a127