Preserve timezone=False for naive Arrow timestamps

[dbascoules]

Description

This PR fixes a regression where DLT dropped the explicit timezone=False hint inferred from naive Arrow timestamps during capabilities adjustment.

Previously, Arrow input with naive timestamps was normalized as if the timezone hint were absent, which caused downstream loading to convert values to UTC-aware timestamps instead of keeping them naive. This affected pass-through behavior for sources that already expose naive Arrow timestamps, including ConnectorX-based extraction.

The fix preserves timezone=False when it is explicitly present on a column, while continuing to strip other timezone values so the default behavior remains unchanged where no explicit hint is set.

Related Issues

• Fixes Naive Arrow timestamps lose timezone=False and are loaded as UTC-aware instead of naive #4015

Additional Context

• Added or updated tests covering naive Arrow timestamps and timezone-aware timestamps.
• Verified the fix with ConnectorX in both arrow and arrow_stream modes.
• Confirmed naive timestamps stay naive in Parquet output and timestamptz values remain UTC-aware.

[rudolfix]

what you say looks right! this behavior is thoroughly tested - I need to see why some of the tests had failed.