Try removing Redshift-specific logic for toggling case-sensitive identifiers

[dbeatty10]

resolves #206

Problem

We have hard-coded logic just for Redshift that toggles a setting to enable case-sensitive identifiers. This makes the code harder to read and maintain.

Solution

1. Ensure that the Redshift cluster for running CI tests has enable_case_sensitive_identifier set to true (rather than the default of false).
2. Remove the prior logic that toggled this setting on an as-needed basis.

Checklist

• This code is associated with an issue which has been triaged and accepted for development.