Update pallet runtime mocks config close to real values

[ukint-vs]

File Location(s)

pallets/*/src/mock.rs

Proposal

To test our pallets we need to use configs that are close to real runtime and update tests accordingly. For example ExistentialDeposit must be much bigger than 500 because our mocked weights are equal to production weights.

[grishasobol]

Corresponding https://github.com/gear-tech/gear/issues/2977