ci : remove missing reranker model files (#16444)
This commit removes jina-reranker-v1-tiny-en model files that are no
longer present on Hugging Face.
The motivation for this that it clears up the CI logs from 404 errors
which can be a little confusing when looking at the logs the first time.
Refs: https://github.com/ggml-org/llama.cpp/actions/runs/18070620247/job/51419855630#step:5:2649
