Add ESCAPE_UNENCLOSED_FIELD Parameter in The Load Table Query's File Format

[williamgagnonpoka]

In the SnowflakeBackend, the query used inside the merge_table() function includes the ESCAPE_UNENCLOSED_FIELD=NONE parameter. However, the query used in the load_table() function does not include this parameter, leading to errors when loading certain rows into Snowflake tables.

For example, a string like "Hello! \" will result in the following error:

End of record reached while expected to parse column.

This PR resolves the issue by adding the ESCAPE_UNENCLOSED_FIELD=NONE parameter to the query used in the load_table() function, ensuring consistency and preventing such errors.