fix(fivetran_sdk): Update guide to not consider backslash as escape char

[fivetran-abdulsalam]

We create CSV split file as:

CsvSchema.Builder builder = CsvSchema.builder();
for (Column c : finalColumns) builder.addColumn(c.name, csvType(c.type));
CsvSchema csvSchema = builder.setUseHeader(true).setNullValue(DataWriter.WAREHOUSE_NULL).build();
CSV.configure(JsonGenerator.Feature.FLUSH_PASSED_TO_STREAM, false);

And by Default in CSVSchema no escape character is used and thus we can create spit file as:

id,val,name,_fivetran_synced
1,"abc , \",abdul,2024-05-09T10:22:59.588Z
2,"abcd ",salam,2024-05-09T10:22:59.621Z

Updated development guide indicating this so partner do not consider backslash as escape character.