Unitxt 1.26.8

What's Changed

• add ollama classification engine by @lilacheden in #1955
• make ollamaInferenceEngine handle return_meta_data by @lilacheden in #1956
• lazy import of evaluate by @assaftibm in #1957
• Update version to 1.26.8 by @elronbandel in #1958

Full Changelog: 1.26.7...1.26.8