COUNT DISTINCT does not support for `Boolean`

[alamb]

Note: migrated from original JIRA: https://issues.apache.org/jira/browse/ARROW-12339

If you try to run a COUNT (DISTINCT ..) query on a boolean column you get the following panic:

thread 'tokio-runtime-worker' panicked at 'Unexpected DataType for list', datafusion/src/scalar.rs:342:22

While there is unlikely to be a big usecase for this, it would be nice for completeness sake. At the very least we should add a proper error message rather than a panic

Reproducer:
{code}
echo "true" > /tmp/foo.csv
./target/debug/datafusion-cli

CREATE EXTERNAL TABLE t (a boolean) STORED AS CSV LOCATION '/tmp/foo.csv';

0 rows in set. Query took 0 seconds.

select count(distinct a) from t;

thread 'tokio-runtime-worker' panicked at 'Unexpected DataType for list', datafusion/src/scalar.rs:342:22
note: run with RUST_BACKTRACE=1 environment variable to display a backtrace
ArrowError(ExternalError(Canceled))
{code}