Update param-ch4.json (#1752)

fix the inconsistent lengths between `sys_batch_size` and `sys_configs`

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## Summary by CodeRabbit

- **Chores**
- Cleaned up configuration by removing redundant entries from the batch
size settings in the JSON file.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Signed-off-by: Yong-Bin Zhuang <38876805+robinzyb@users.noreply.github.com>

Author: robinzyb

examples/run/dp2.x-lammps-cp2k/methane/param-ch4.json

@@ -23,8 +23,6 @@
         ]
     ],
     "sys_batch_size": [
-        8,
-        8,
         8,
         8
     ],