Parse sequence type and integer metadata in dumpSequence().

Parse sequence type and integer metadata in dumpSequence().

This commit modifies dumpSequence() to parse all the sequence
metadata into the appropriate types instead of carting around
string pointers to the PGresult data.  Besides allowing us to free
the PGresult storage earlier in the function, this eliminates the
need to compare min_value and max_value to their respective
defaults as strings.

This is preparatory work for a follow-up commit that will improve
the performance of dumpSequence() in a similar manner to how commit
2329cad1b9 optimized binary_upgrade_set_pg_class_oids().

Reviewed-by: Euler Taveira
Discussion: https://postgr.es/m/20240503025140.GA1227404%40nathanxps13