feat: handle unexpected unbonding tx

[gusin13]

This pr

1. refactors/optimizes the spend notification logic
2. intercepts the unknown unbonding tx case as discussed in this slack thread, this will enable the API to transition such delegations to Unbonding (this will be the final state for such case and such delegations will be stuck at Unbonding, as we don't know if it can be withdrawn)

Note - metrics will be added in separate PR

[jrwbabylonlab]

IMO, we shall get help from core team to investigate the root case first. Otherwise we are adding unnecessary logic and entry in db.

[gusin13]

@jrwbabylonlab
We still need indexer to handle this case, this is something that Babylon does too i.e when receiving such tx it marks the delegation as "Unbonded" in its internal db. - code link

[gitferry]

I think unexpected unbonding txs will be caught by IsValidUnbondingTx. Probably no need to consume the event from Babylon. It also makes think that maybe we can just do the same way used in Babylon (link) to identify unexpected unbonding tx (checking whether the hash matches to the unbonding tx in the delegation). We can do it now because now we have enforced that unbonding tx must be the same as the one in eoi

[gusin13]

@gitferry I have made the above discussed changes, can you please re-review

I deployed and tested this pr on devnet and the concerned delegation in devnet 91f0466163870397682e0cbc76cc132bc8734ede295e2d6950ba5f945533b5ab
which is discussed in this slack thread
is now being marked as Unbonding. Logs link - https://grafana.tooling.babylonlabs.io/goto/Jj1qjxvNR?orgId=1

[gusin13]

@gitferry i have made further changes in pr as per our call.

• removes the isValidUnbondingTx and uses multiple smaller functions instead isSpendingStakingTxUnbondingPath, validateUnbondingTxOutput
• also updates the state (we discussed to do this in separate pr but the scope was very overlapping so while coding i realized it might be better to add now)

regarding the improvement of slashing - it will be done in separate pr

[gitferry]

Thanks for the change. Great work!