Add extras to installtion of wwb to tests/llm (#34470)

### Details:
- install specific extension of wwb module for llm accuracy tests to
avoid too complex dependency structure
Corresponding PR to WWB requirements in openvino.genai
openvinotoolkit/openvino.genai#3439

### Tickets:
 - [CVS-181664](https://jira.devtools.intel.com/browse/CVS-181664)

### AI Assistance:
 - no

Author: sbalandi

tests/llm/requirements.txt

@@ -1,6 +1,6 @@
 -c ../constraints.txt
 --extra-index-url https://download.pytorch.org/whl/cpu
 optimum-intel[tests,nncf]
-whowhatbench @ git+https://github.com/openvinotoolkit/openvino.genai.git#subdirectory=tools/who_what_benchmark
+whowhatbench[llm-test-openvino] @ git+https://github.com/openvinotoolkit/openvino.genai.git#subdirectory=tools/who_what_benchmark
 pytest
 jinja2>=3.1.0