[TASK] Upgrade testnet + mainnet w/ polkadot-sdk update

[drewstone]

From @1xstj

The finalisation issue on testnet that we reported long back (paritytech/polkadot-sdk#3487) was actually a bug in substrate and was patched on Friday (paritytech/polkadot-sdk#5153). Unfortunately the same issue broke our testnet again, so we will have to upgrade tangle to the next release with this patch asap.