Deprecate ScalarValue::get_datatype()

[alamb]

Is your feature request related to a problem or challenge?

We introduced ScalarValue::data_type() in #7492 to be consistent with other APIs for getting DataType.

However the previous ScalarValue::get_datatype()

#7492 (comment)

Describe the solution you'd like

1. Mark ScalarValue::get_datatype() deprecated (like this):

https://github.com/apache/arrow-datafusion/blob/93c209f1b5d0a17b2aa5c6743cbd3cb189a406c8/datafusion/expr/src/table_source.rs#L81-L87

2. Update the uses in the datafusion codebase to pass clippy (update to use ScalarValue::data_type())

Describe alternatives you've considered

No response

Additional context

No response

[Weijun-H]

I will be glad to handle this later.