Quoted user names are now always case-sensitive regardless of enable_case_sensitive_identifier setting

[winglot]

The case of a username enclosed in double quotation marks is always preserved regardless of the setting of the enable_case_sensitive_identifier configuration option.

https://docs.aws.amazon.com/redshift/latest/dg/r_enable_case_sensitive_identifier.html

The provider always encloses usernames but saves the value to the state as lowercase.
This must be some recent change since tests that have been in the provider from the beginning are now failing