Glows - final flags

[laspsandoval]

This pull request enhances the GLOWS L1b data processing by implementing new per-bin quality flags for instrument team exclusions and suspected transients, improves the flagging logic, and updates tests and supporting data structures accordingly. The changes make the flagging system more robust and allow for more granular data quality tracking.

Enhancements to flagging logic and data structures:

• Added new per-bin flags IS_EXCLUDED_BY_INSTR_TEAM and IS_SUSPECTED_TRANSIENT to the GLOWSL1bFlags enum in imap_processing/quality_flags.py, enabling more detailed quality tracking.
• Implemented the flag_from_mask_dataset method in GLOWSL1bData to retrieve per-bin boolean masks from xarray datasets, supporting the new exclusion and transient flags.
• Updated _compute_histogram_flag_array to populate the new flags using the mask datasets, and removed outdated TODOs now that the logic is implemented. [1] [2]

Test and fixture improvements:

• Updated the mock_ancillary_exclusions fixture to provide realistic l1b_unique_block_identifier and histogram_mask_array values for both instrument team exclusions and suspected transients, enabling more accurate testing. [1] [2]
• Expanded tests in test_glows_l1b.py to verify the correct operation of flag_from_mask_dataset, including shape and count checks for the exclusion mask.

Minor code organization:

• Moved the generation of the unique_block_identifier in __post_init__ for clarity and to ensure correct initialization order.

[laspsandoval]

@maxinelasp does this close this ticket too? #2688

Or is there more to do?