Misuse of balance lock

[sameh-farouk]

Describe the bug

By reviewing the billing code, it seems that the balance lock feature (from the balances pallet) may have been used incorrectly in our smart-contract pallet (at least it wasn't intended for such a use case).

Here are some side effects that I can think of:

• I have observed that at times, we unintentionally lock amounts more than the due one.
• While checking if a contract should be moved into the grace period or restored, we do not consider the previously locked amount. This can lead to the contract going into the grace period earlier than expected or requiring additional funds to get restored.
• There is a possibility that this issue may cause failure while distributing rewards.
• Even after canceling all contracts and paying all due amounts still leave part of the user balance locked unexpectedly

I can provide more details later (issue to be updated)

To Reproduce

Expected

Screenshots

Additional context

[0oM4R]

I'm working on https://github.com/threefoldtech/tfgrid-sdk-ts/issues/2489 , and while testing the flow, i had total locked amount with less than 19 tft, balance details :

i have funded my wallet with 19 tft, i was expecting to bill all of them, but after call billContractForBlock for all contracts, all contracts moved back to created state, I my balance details :

locks like there is somthing wrong with rent contract billing