Fix strpos first arg null warning in php 8.1

[kirtangajjar]

Description of the Change

Fix strpos first arg null warning in php 8.1

Closes #1175

How to test the Change

Follow steps in linked issue.

Changelog Entry

Fixed - strpos first arg null warning in php 8.1

Credits

Props @kirtangajjar

Checklist:

• [x] I agree to follow this project's Code of Conduct.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my change.
• [x] All new and existing tests pass.