Fix prefix updater

[kmcginnes]

Description

This fixes an issue with RDF data sets that contain upper case characters in the URI. For example:

http://www.ExampleData.com/Entity

These uppercase characters would cause the prefix generator to miss the existing entry in the prefixes array, causing a new entry to be created. That new entry would be converted to lower case. On the next pass the same thing would happen looped to infinity.

This infinite loop would cause Graph Explorer to crash.

To fix, I made the search for an existing entry be case insensitive.

Validation

• Tested with dataset that produces the crash
• Added unit tests for case sensitivity

Related Issues

• Resolves [Bug] Crash in RDF databases with upper case characters in the URI #545

Check List

• I confirm that my contribution is made under the terms of the Apache 2.0
  license.
• I have run pnpm checks to ensure code compiles and meets standards.
• I have run pnpm test to check if all tests are passing.
• I have covered new added functionality with unit tests if necessary.
• I have added an entry in the Changelog.md.