fix(clickhouse): avoid forcing UTC to allow connection to servers that do not allow it

[cpcloud]

Fixes the ability to connect to clickhouse playground. From this Zulip topic.

[cpcloud]

Manual testing:

In [1]: from ibis.interactive import *

In [2]: con = ibis.clickhouse.connect(
   ...:     host="clickpy-clickhouse.clickhouse.com", database="pypi", secure=True, user="play"
   ...: )

In [3]: con.list_tables()
Out[3]:
['countries',
 'countries_dict',
 'last_updated_dict',
 'projects',
 'pypi',
 'pypi_downloads',
 'pypi_downloads_by_version',
 'pypi_downloads_by_version_mv',
 'pypi_downloads_max_min',
 'pypi_downloads_max_min_mv',
 'pypi_downloads_mv',
 'pypi_downloads_per_day',
 'pypi_downloads_per_day_by_version',
 'pypi_downloads_per_day_by_version_by_country',
 'pypi_downloads_per_day_by_version_by_country_mv',
 'pypi_downloads_per_day_by_version_by_file_type',
 'pypi_downloads_per_day_by_version_by_file_type_mv',
 'pypi_downloads_per_day_by_version_by_installer_by_type',
 'pypi_downloads_per_day_by_version_by_installer_by_type_by_country',
 'pypi_downloads_per_day_by_version_by_installer_by_type_by_country_mv',
 'pypi_downloads_per_day_by_version_by_installer_by_type_mv',
 'pypi_downloads_per_day_by_version_by_python',
 'pypi_downloads_per_day_by_version_by_python_by_country',
 'pypi_downloads_per_day_by_version_by_python_by_country_mv',
 'pypi_downloads_per_day_by_version_by_python_mv',
 'pypi_downloads_per_day_by_version_by_system',
 'pypi_downloads_per_day_by_version_by_system_by_country',
 'pypi_downloads_per_day_by_version_by_system_by_country_mv',
 'pypi_downloads_per_day_by_version_by_system_mv',
 'pypi_downloads_per_day_by_version_mv',
 'pypi_downloads_per_day_mv',
 'pypi_downloads_per_month',
 'pypi_downloads_per_month_mv']