FCs detection needs tests

[kkappler]

Now that #358 is fixed but another issue has come up;

If the FCs are there but I want to process with a different processing config, like a different apodization window, the FCs present should be false. I'm not seeing that happen on the earthscope server with an mth5 that has some FCs embedded.

Need to scrub the logic in:

aurora/pipelines/transfer_function_kernel.py:176: def check_if_fcs_already_exist(self):