Modify to make rerank provider works to llama.cpp rerank API

[ziyu4huang]

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1. Is this request related to a challenge you're experiencing? Tell me about your story.

Recently, llama.cpp support rerank , I modify provider to solve llama.cpp API problem not return text.

See llama.cpp issue

2. Additional context or comments

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3. Can you help us with this feature?

• I am interested in contributing to this feature.

[ziyu4huang]

I have verify using latest llama.cpp, run with below option
./llama.cpp/build_hip/bin/llama-server --host 0.0.0.0 --port 8090 -c 8128 -m ./gguf/bge-reranker-v2-m3-Q4_K_M.gguf --reranking

Test use local-ai provider . It works well.

slot launch_slot_: id 0 | task 92 | processing task
slot update_slots: id 0 | task 92 | tokenizing prompt, len = 2
slot update_slots: id 0 | task 92 | prompt tokenized, n_ctx_slot = 8128, n_keep = 0, n_prompt_tokens = 48
slot update_slots: id 0 | task 92 | kv cache rm [0, end)
slot update_slots: id 0 | task 92 | prompt processing progress, n_past = 48, n_tokens = 48, progress = 1.000000
slot update_slots: id 0 | task 92 | prompt done, n_past = 48, n_tokens = 48
slot release: id 0 | task 92 | stop processing: n_past = 48, truncated = 0
slot launch_slot_: id 0 | task 93 | processing task
slot update_slots: id 0 | task 93 | tokenizing prompt, len = 2
slot update_slots: id 0 | task 93 | prompt tokenized, n_ctx_slot = 8128, n_keep = 0, n_prompt_tokens = 54
slot update_slots: id 0 | task 93 | kv cache rm [0, end)
slot update_slots: id 0 | task 93 | prompt processing progress, n_past = 54, n_tokens = 54, progress = 1.000000
slot update_slots: id 0 | task 93 | prompt done, n_past = 54, n_tokens = 54
slot release: id 0 | task 93 | stop processing: n_past = 54, truncated = 0
srv update_slots: all slots are idle
request: POST /rerank 172.30.0.7 200