[EPLB]Eplb Config Renaming (#5533)

### What this PR does / why we need it?
1. Rename num_iterations_eplb_update to expert_heat_collection_interval.
2. Rename num_wait_worker_iterations to algorithm_execution_interval.
3. Rename init_redundancy_expert to num_redundant_experts because the
variable with the same meaning in vLLM is named this way.
4. Delete gate_eplb because we don't need this feature.
5. Move eplb config into a dict in additional config.
6. Depend on pr5817

### Does this PR introduce _any_ user-facing change?

before this pr：
`--additional-config '{"dynamic_eplb":true,
"num_iterations_eplb_update": 4000, "num_wait_worker_iterations": 150,
"init_redundancy_expert": 16, "expert_map_path": "xxx.json"}'`

after this pr: 
`--additional-config
'{"eplb_config":{"dynamic_eplb":true,"expert_heat_collection_interval":4000,
"algorithm_execution_interval":150,"num_redundant_experts": 16,
"expert_map_path": "xxx.json"}}'`

### How was this patch tested?

#### test qwen3-235b eplb num_redundant_experts=16

without pr5817
| dataset | version | metric | mode | vllm-api-general-chat |
|----- | ----- | ----- | ----- | -----|
| aime2024 | 604a78 | accuracy | gen | 83.33 |

with pr5817
| dataset | version | metric | mode | vllm-api-general-chat |
|----- | ----- | ----- | ----- | -----|
| aime2024 | 604a78 | accuracy | gen | 86.67 |

- vLLM version: v0.13.0
- vLLM main:
45c1ca1ca1

Signed-off-by: shenchuxiaofugui <1311027364@qq.com>

tests/e2e/multicard/2-cards/test_qwen3_moe.py

@@ -105,10 +105,12 @@ async def test_qwen3_moe_w8a8_distributed_tp2_ep_dynamic_eplb():
     # during initialization in offline mode, so the online mode is used instead.
     env_dict.update({"DYNAMIC_EPLB": "true"})
     additional_config = {
-        "dynamic_eplb": True,
-        "num_iterations_eplb_update": 100,
-        "num_wait_worker_iterations": 20,
-        "num_redundant_experts": 2
+        "eplb_config": {
+            "dynamic_eplb": True,
+            "expert_heat_collection_interval": 100,
+            "algorithm_execution_interval": 20,
+            "num_redundant_experts": 2
+        }
     }
     server_args.extend(["--additional-config", json.dumps(additional_config)])
     with RemoteOpenAIServer(model,