fix(utils): import ProgrammingError instead of bare exc. reference

[vikrantpuppala]

Summary

ParamEscaper.escape_args and ParamEscaper.escape_item both raise exc.ProgrammingError(...) (lines 551 and 609 of utils.py), but exc is never imported. On any unsupported parameter shape the user sees NameError: name 'exc' is not defined instead of a clean PEP-249 ProgrammingError.

Surfaced via the python-comparator audit harness running the INLINE_PARAMS connection config: both backends raised NameError: name 'exc' is not defined, which the comparator's class+message match treated as parity — a false-positive that hid both the real driver bug and the underlying caller-side type mismatch.

Fix

Import ProgrammingError directly from databricks.sql.exc (matching the pattern used in session.py, client.py, result_set.py, etc.) and replace the two exc.ProgrammingError(...) sites with bare ProgrammingError(...).

Test plan

• Manual repro: pe = ParamEscaper(); pe.escape_args(object()) now raises ProgrammingError, not NameError. Same for pe.escape_item(object()).
• Existing test suite — no behaviour change beyond the exception class on a previously-unreachable error path.

This pull request and its description were written by Isaac.

[vikrantpuppala]

Folded into #803 as part of a bundle of five comparator-parity fixes that share the same audit baseline. The exc.ProgrammingError import fix is item #5 in the updated #803 description. Closing this in favour of the bundled review.