SN0 Stake Add is incorrect stake fee

[thewhaleking]

https://github.com/opentensor/subtensor/blob/737e4acb173cddbe6fde9c6085853ef8b8f02a80/pallets/subtensor/src/staking/stake_utils.rs#L567

and since SubnetMechanism is 0, there's no fee: https://github.com/opentensor/subtensor/blob/737e4acb173cddbe6fde9c6085853ef8b8f02a80/pallets/subtensor/src/staking/stake_utils.rs#L591

[camfairchild]

We can use the new runtimeAPI instead so we don't have to have logic re-implemented around it

[camfairchild]

swapRuntimeApi.simSwapTaoForAlpha(netuid, tao_amt), and.
swapRuntimeApi.simSwapAlphaForTao(netuid, alpha_amt)