AZFP: Move computing of Sv offset outside of setting of Vendors and test for Sv offset using ASL/Rutgers Data

[ctuguinay]

• Create the Sv_offset dataset in the AZFP parser and pack it in parser_obj.unpacked_data
• Make the error message in the Sv offset frequency check more specific (Wu-Jung posted below)
• When ASL/Rutgers AZFP data arrives, write tests for skipped tests from Update _calc_Sv_offset for AZFP parsing #1304

[leewujung]

Just realized that the error message can be more specific to add the freq for the second check, so maybe we include that in this next PR also:

        # Check if the specified freq-pulse length combination is in the allowable Sv_offset dict
        if pulse_len not in SV_OFFSET[freq]:
            raise ValueError(
                f"Pulse length {pulse_len} us is not in the Sv offset dictionary "
                "for the {freq} Hz channel! "  # add freq info
                "Please contact AZFP Environmental Sciences "
                "and raise an issue in the echopype repository."
            )

[ctuguinay]

Sounds good 👍