Describe Your Changes

This pull request includes updates to the engine installation tests to change the variant of the llama-cpp engine. The changes ensure that the tests now use the linux-amd64-avx variant instead of the previous linux-amd64-avx-cuda-11-7 variant.

Changes to engine installation tests:

• engine/e2e-test/api/engines/test_api_engine.py: Updated the test_engines_install_llamacpp_specific_version_and_variant method to use the linux-amd64-avx variant.
• engine/e2e-test/api/engines/test_api_engine_install_nightly.py: Updated the test_engines_install_llamacpp_specific_version_and_variant method to use the linux-amd64-avx variant.
• engine/e2e-test/api/engines/test_api_get_default_engine.py: Updated the test_api_get_default_engine_successfully method to use the linux-amd64-avx variant.

Fixes Issues

• Closes #
• Closes #

Self Checklist

• Added relevant comments, esp in complex areas
• Updated docs (for bug fixes / features)
• Created issues for follow-up changes or refactoring needed