Fix memory leak error afer adding schema metadata

[Gor027]

Build and Cassandra workflows did not report definitely lost memory leaks as errors and support for fetching schema metadata was merged with memory leaks.

Fixed memory leaking error and added appropriate options to valgrind to report only definitely lost memory as error.

Pre-review checklist

• [x] I have split my patch into logically separate commits.
• [x] All commit messages clearly explain what they change and why.
• [x] PR description sums up the changes and reasons why they should be introduced.
• [x] I have enabled appropriate tests in .github/workflows/build.yml in gtest_filter.
• [x] I have enabled appropriate tests in .github/workflows/cassandra.yml in gtest_filter.

[Gor027]

@Lorak-mmk While debugging and testing #76 to prevent memory leaks I found that the schema metadata related PR #72 was merged still having some memory leaks that the GitHub Actions workflows did not detect and report. I hope this PR will prevent such cases in the future.