Support for EK80 Broadband Complex Multiplex Data

[ctuguinay]

Addresses #743 and #1287.

Calibration Code Changes:

• In compress_pulse, the convolution operation handles NaNs by turning them into 0s and turning them back into NaNs post-convolution.
• In get_transmit_signal, filtered out NaNs from tx_params
  • The code itself still doesn't accept multiple unique non-NaN tx_params, but that should be a separate PR.
• In harmonize_env_param_time, separated out the single time1 when drop NaN case from single time1 without drop NaN case.
  • This was done specifically for the case where EK80 multiplex data has 1 time1 dimension and has alternating NaN / non-NaN pattern. When drop NaN on the time1 dimension is called on the multiplex data array, it will drop ALL values of the array, which is not the desired behavior.
• In gain compensation operation, zero out NaNs that appear due to 1) multiplex ping patterns and 2) single beam transducer systems that don't contain angle offset information.

Small Change

• Set Xarray DataArray/Dataset drop to drop_vars, since drop is now deprecated

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 89.12%. Comparing base (9f56124) to head (bc833c8). Report is 48 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1302 +/- ## ========================================== + Coverage 83.52% 89.12% +5.60% ========================================== Files 64 11 -53 Lines 5686 984 -4702 ========================================== - Hits 4749 877 -3872 + Misses 937 107 -830 ``` | [Flag](https://app.codecov.io/gh/OSOceanAcoustics/echopype/pull/1302/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=OSOceanAcoustics) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/OSOceanAcoustics/echopype/pull/1302/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=OSOceanAcoustics) | `89.12% <100.00%> (+5.60%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=OSOceanAcoustics#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[leewujung]

Ok, after some fiddling I found that many other parts of the calibration code does not currently support a fully lazy-loaded EchoData object, mostly due to "Indexing with a boolean dask array is not allowed". Those boolean indexing places are all pretty small under the current constraint that the transmit signal type are identical across ping_time (so can change across channel), so it may be fine to force compute them, but we need to do some more experiment and benchmarking.

That is outside the scope of this PR though, so I'll merge this PR first. Thanks for the investigations and changes to address the alternating channel issue!