`CREATE EXTERNAL TABLE ... STORED AS CSV with header row` fails when `with header row` is lowercase

[alamb]

Describe the bug
Currently, creating an external table using datafusion-cli with this sql:

CREATE EXTERNAL TABLE t(c1 int) STORED AS CSV with header row LOCATION 'foo.csv'

will fail when with header row tokens are in lower case.

To Reproduce
Steps to reproduce the behavior:

Expected behavior
A clear and concise description of what you expected to happen.

Additional context
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