Feature/bugfix smap rss l2 sss v6

[sliu008]

Description

• Fix SMAP_RSS_L2_SSS_V6 for l2ss-py
• Fix Mistaken report of subsetted area being equal to original granule #197

Overview of work done

• Update the indexer function to account for 3 dimension on the
• update indexer when the lon lat has dims xdim_grid and ydim_grid
• make indexer account for when the x index is on 1 and y index is on 0 we don't need to transpose the dimensions
• update the logging when we have empty dataset in indexer and when we are selecting everything in indexer

Overview of verification done

• pytest locally make sure still pass test
• tested with SMAP_RSS_L2_SSS_V6 granules to make sure subsettings correct

PR checklist:

• Linted
• Updated unit tests
• Updated changelog
• Integration testing

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