[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/ut/test_ascend_config.py

@@ -37,7 +37,6 @@ class TestAscendConfig(TestBase):
         test_vllm_config = VllmConfig()
         # No additional config given, check the default value here.
         ascend_config = init_ascend_config(test_vllm_config)
-        self.assertIsNone(ascend_config.expert_map_path)
         self.assertFalse(ascend_config.multistream_overlap_shared_expert)
         self.assertFalse(ascend_config.enable_kv_nz)
 
@@ -52,12 +51,14 @@ class TestAscendConfig(TestBase):
                 "fuse_norm_quant": False,
             },
             "multistream_overlap_shared_expert": True,
-            "expert_map_path": "test_expert_map_path",
+            "eplb_config": {
+                "num_redundant_experts": 2
+            },
             "refresh": True,
             "enable_kv_nz": False
         }
         ascend_config = init_ascend_config(test_vllm_config)
-        self.assertEqual(ascend_config.expert_map_path, "test_expert_map_path")
+        self.assertEqual(ascend_config.eplb_config.num_redundant_experts, 2)
         self.assertTrue(ascend_config.multistream_overlap_shared_expert)
         self.assertFalse(ascend_config.enable_npugraph_ex)