[Core] Refactor omni prefix cache into Manager/Controller (#6654)

Signed-off-by: ZhengWG <zwg0606@gmail.com>
Co-authored-by: amy-why-3459 <wuhaiyan17@huawei.com>
Co-authored-by: Hongsheng Liu <liuhongsheng4@huawei.com>

tests/model_executor/models/voxcpm2/test_runner_assisted_unified_graph_static.py

@@ -74,7 +74,9 @@ def test_ar_runner_without_model_hook_stays_on_normal_path():
     assert "exceptException" not in compact_request_source
 
     set_context_source = source[source.index("def _set_runner_assisted_full_attention_metadata_context") :]
-    set_context_source = set_context_source[: set_context_source.index("def _deferred_prefix_cache_mm_keys")]
+    set_context_source = set_context_source[
+        : set_context_source.index("def _prepare_prefix_cache_pooler_payload_sources")
+    ]
     assert "except Exception" not in set_context_source