fix(mssql): avoid calling .commit() unless a DDL operation is being performed

[cpcloud]

This PR attempts to address flaky behavior of MS SQL observed in CI.

It seems like calling commit()/rollback() with a SELECT statement, AKA autocommit behavior
can cause this issue.

The origin is not 100% clear to me, but there are a number of places where the
same problem (function sequence error) with the same solution show up
(disabling autocommit or not calling commit with a SELECT statement):

• https://stackoverflow.com/questions/25769043/function-sequence-error-in-pyodbc
• odbc : [HY010] [unixODBC][Driver Manager]Function sequence error (0) (SQLFetch) ansible-collections/community.general#1137
• https://www.reddit.com/r/learnpython/comments/x8568m/function_sequence_error_in_sqlalchemy/
• All Queries Produce "[HY010][Microsoft][ODBC Driver for SQL Server] Function sequence error (0) (SQLFetch)" explorerhq/sql-explorer#423

Here I avoid calling cur.commit() unless a DDL statement is being executed.

The remaining case is raw_sql(), which I opted to avoid calling commit in
since that would have this problem when calling it with a SELECT statement.

Users of raw_sql are therefore responsible for handling commit/rollback when
invoking it for DDL statements.

Closes #9654.

[gforsyth]

thanks for tracking this down!