Refactor testutil/keeper.FungibleKeeper to use mocks for dependent modules

[lumtis]

Part of #878

Fungible test keeper currently use empty instances for dependences

bankkeeper := bankkeeper2.BaseKeeper{}
authkeeper := authkeeper2.AccountKeeper{}
evmKeeper := evmkeeper.Keeper{}

which makes it not usable for most unit tests. The ideal model for unit tests would be to use mocking for the dependent modules.

Example using Mockery https://github.com/vektra/mockery

• Use the mockery commands to generate the module mocks under mocks

testutil/
  keeper/
    fungiblemocks/
      bank.go
      auth.go
      evm.go

Returns the mocks along with the test keeper in FungibleKeeper

func FungibleKeeper(t testing.TB) (
  *keeper.Keeper,
  fungiblemocks.BankKeeperMock,
  fungiblemocks.AccountKeeperMock,
  fungiblemocks.EVMKeeperMock,
  sdk.Context,
)