[BugFix] detection jinja2 (#7251)

* detection jinja2

* format

custom_ops/gpu_ops/moe/moe_wna16_marlin_utils/generate_kernels.py

@@ -5,7 +5,12 @@ import itertools
 import os
 import subprocess
 
-import jinja2
+try:
+    import jinja2
+except ImportError:
+    raise ImportError(
+        "jinja2 is required to generate marlin moe wna16 kernels. " "Please install it with: pip install jinja2"
+    )
 
 FILE_HEAD = """
 // auto generated by generate.py