SET Bug related to geo2rdr (duplicate state vectors)

[cmarshak]

Resolves #145 - the subsequent error obtained locally (thanks @mgovorcin for graciously pointing this out!).

We fix it in a number of ways:

• ensure the localized metadata dictionary has unique orbit xmls
• ISCE2 orbit object is created with unique xmls of list passed

[cmarshak]

To be clear, the SET error was raised at this point in the main workflow.

We used #142 GUNW example to debug. Since there are two SLCs for each date (reference/secondary), each SLC for a given date will provide an orbit for the SET correction in via localize_orbit.py (the same orbit file in fact).

The error was raised when we ran:

nc_path = update_gunw_with_solid_earth_tide(nc_path, "reference", loc_data['reference_orbits'])

but not if we ran:

nc_path = update_gunw_with_solid_earth_tide(nc_path, "reference", loc_data['reference_orbits'][:1])

The orbits were:

[PosixPath('orbits/S1A_OPER_AUX_POEORB_OPOD_20220304T081601_V20220211T225942_20220213T005942.EOF'),
 PosixPath('orbits/S1A_OPER_AUX_POEORB_OPOD_20220304T081601_V20220211T225942_20220213T005942.EOF')]

Note that these are duplicated and hence the fix proposed above.