fix concat dictionary(int32, utf8) bug

[thinh2]

Which issue does this PR close?

Closes #12101 .

Rationale for this change

Before this change, query to concat 2 dictionary columns will return error. This PR is to add support for concat dictionary columns in string_concat_coercion function.

What changes are included in this PR?

• Add handler for string_concat_cocercion where lhs and rhs are Dictionary.
• Update the sqllogictest to match the expectaion. There should be no error when concat columns or values of type Dictionary(int32, utf8)

Are these changes tested?

• The sqllogictest is updated to match the expectation query results.

Are there any user-facing changes?

[alamb]

Thank you @thinh2 -- this looks perfect 🙏