Timestamps without a timezone should be able to coerce to Timestamp types with a timezone

[mhilton]

Is your feature request related to a problem or challenge?

Function calls that require a parameter that is a timestamp type that includes a timezone cannot currently accept a timestamp without a timezone unless the latter is explicitely cast to the correct type.

Describe the solution you'd like

The coercioin rules should be updated to automatically coerce from Timestamp(, None) to Timestamp(, Some(_)).

Describe alternatives you've considered

No response

Additional context

No response