Enhance file_fdw to report processed and skipped tuples in COPY progress

Hi,

Currently, file_fdw updates several columns in the pg_stat_progress_copy view,
like relid and bytes_processed, but it doesn't track tuples_processed or
tuples_skipped. Monitoring these would be particularly useful when handling
large data sets via file_fdw, as it helps track the progress of scan.

The attached patch updates file_fdw to add support for reporting
the number of tuples processed and skipped (due to on_error = 'ignore')
in the pg_stat_progress_copy view. What are your thoughts?

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION