Fixes #15659

This partially reverts #12759 for VARCHAR columns.

Previously parameters would always count as literals - i.e. passing in a parameter 1 would bind as an INTEGER_LITERAL, and a parameter 'str' would bind as a string literal. This matters because literals have special binding rules where they adopt surrounding types, so string literals can be used as dates, but VARCHAR columns cannot (see literal typing here)

For integer literals this fixes issues where types were ignored causing overflow errors when used in conjunction with smaller integer types. For string literals, however, this can cause previously working code to now throw binder errors. This PR reverts the behavior so that the code in the linked issue works again.