Describe the bug

If you create a table with a struct column where a field in the struct include a capital letter then the query planner will complain that it cannot find that field.

To Reproduce

1. Create a JSON file named "test.json" with content:

{"thing": {"fooBar": "not going to find me"}}

2. Start the Datafusion cli
3. Execute "select thing.fooBar from 'test.json';"

Actual: The query will fail saying 'Error during planning: Field foobar not found in struct'.
Expected: The query executes returning 1 row with content "not going to find me"

Note: if you change the content of the file to:

{"thing": {"foobar": "not going to find me"}}

where the only change is "fooBar" to "foobar" then everything works.

Expected behavior

Expected: The query executes returning 1 row with content "not going to find me"

Note: if you change the content of the file to:

{"thing": {"foobar": "not going to find me"}}

where the only change is "fooBar" to "foobar" then everything works.

Additional context

Repros on 46.0.0 and 48.0.0