Handle Case sensitivity in indexed and included column names appropriately

[apoorvedave1]

Describe the issue

Handle case-sensitivity in indexed and included column names appropriately based on the value of "spark.sql.caseSensitive".

Here's the desired behavior
Q. If case-sensitive = true, index config is wrong case, will createIndex work? No. Fail, exception.
Q. If case-sensitive = false, index config is wrong case, will createIndex work? Yes.
Q. If case-sensitive = true, an index exists with wrong case, will this index be used? No. Ignore this index
Q. If case-sensitive = false, an index exists with wrong case, will this index be used? Yes.

To Reproduce

NA

Expected behavior

Here's the desired behavior
Q. If case-sensitive = true, index config is wrong case, will createIndex work? No. Fail, exception.
Q. If case-sensitive = false, index config is wrong case, will createIndex work? Yes.
Q. If case-sensitive = true, an index exists with wrong case, will this index be used? No. Ignore this index
Q. If case-sensitive = false, an index exists with wrong case, will this index be used? Yes.

Environment

NA