Remove .c_str() where string_view is expected

[ranisalt]

Pull Request Prelude

• I have followed proper The Forgotten Server code styling.
• I have read and understood the contribution guidelines before making this PR.
• I am aware that this PR may be closed if the above-mentioned criteria are not fulfilled.

Changes Proposed

string_views are optimized to work with strings, there is no need for c_str here (probably just some legacy code)