Exporting line breaks interrupts CSV formatting

[max-hoffman]

Exporting invalid CSV makes it hard to roundtrip import/exports.

Small repro:

dolt init
dolt sql <<EOF
create table ab (a int primary key, b varbinary(255));
insert into ab values (1, 'line\nbreak'), (2,'sorry\ncsv');
EOF
dolt table export ab ab.csv

$ cat ab.csv
a,b
1,"line
break"
2,"sorry
csv"