`server`: inject date_string in llama 3.x template + fix date for firefunction v2...

`server`: inject date_string in llama 3.x template + fix date for firefunction v2 (#12802)

* Inject date_string in llama 3.x + fix for functionary v2

https://github.com/ggml-org/llama.cpp/issues/12729

* move/fix detection of functionary v3.1 before llama 3.x, fix & test their non-tool mode

Co-authored-by: Sigbjørn Skjæret <redacted>
* generate more tokens in test_completion_with_required_tool_tiny_fast to avoid truncation

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Co-authored-by: ochafik <redacted>
Co-authored-by: Sigbjørn Skjæret <redacted>