[VL] Issues related to Timestamp type

### Description

Let's track issues related to Timestamp type here.

* Casting between Timestamp and other types is not fully supported.
See validation check [here](https://github.com/apache/incubator-gluten/blob/main/cpp/velox/substrait/SubstraitToVeloxPlanValidator.cc#L258).
* Casting semantic difference.
1) E.g., Spark allows lacking hour/minute/second part when casting String to Timestamp.
2) https://github.com/apache/incubator-gluten/issues/4433
* Unsupported timezones. Timezone is often involved when handling Timestamp.
* Timestamp precision loss in data serialization. Fixed by https://github.com/apache/incubator-gluten/pull/5376.

Start with cpp/velox/substrait/SubstraitToVeloxPlanValidator.cc at the linked validation check, then review issue #4433 and pull request #5376. Separate the remaining casting, semantic, timezone, and precision concerns, and identify the relevant tests or entry points for each. Done means each supported Timestamp case is resolved with coverage, while this tracking issue no longer contains unscoped work.

Written by the indexing model from the issue text.