Use p_examples path for pwmat test file instead of direct path

Co-authored-by: njzjz <9496702+njzjz@users.noreply.github.com>

Author: Copilot

tests/test_check_examples.py

@@ -163,8 +163,8 @@
         / "param_C4H16N4_deepmd-kit-2.0.1.json",
     ),
     (run_jdata, p_examples / "run" / "dprc" / "generator.json"),
-    # pwmat test file from tests/generator
-    (run_jdata, Path(__file__).parent / "generator" / "param-pyridine-pwmat.json"),
+    # pwmat test file from examples
+    (run_jdata, p_examples / "run" / "deprecated" / "dp2.x-lammps-pwmat" / "param_CH4.json"),
     # machines
     (run_mdata, p_examples / "machine" / "DeePMD-kit-2.x" / "lebesgue_v2_machine.json"),
     (run_mdata, p_examples / "machine" / "DeePMD-kit-1.x" / "machine-local.json"),