[C++][Dataset] Pass schema including all materialized fields to catch CSV edge cases

[asfimport]

see discussion here #7033 (comment)

Fields filtered but not projected will revert to their inferred type, whatever their dataset's schema may be. This can cause validated filters to fail due to type disagreements

Reporter: Ben Kietzman / @bkietz
Assignee: Ben Kietzman / @bkietz

Related issues:

• [C++][Dataset] Make Expressions available for projection (is fixed by)

_{Note: This issue was originally created as ARROW-8630. Please see the migration documentation for further details.}