fix _try_import function not defined issue in fabric

Author: jingxu10

src/lightning/fabric/utilities/imports.py

@@ -36,6 +36,17 @@
 _PYTHON_GREATER_EQUAL_3_10_0 = (sys.version_info.major, sys.version_info.minor) >= (3, 10)
 
 
+@functools.lru_cache(maxsize=128)
+def _try_import_module(module_name: str) -> bool:
+    try:
+        __import__(module_name)
+        return True
+    # added also AttributeError fro case of impoerts like pl.LightningModule
+    except (ImportError, AttributeError) as err:
+        rank_zero_warn(f"Import of {module_name} package failed for some compatibility issues: \n{err}")
+        return False
+
+
 @functools.lru_cache(maxsize=1)
 def _lightning_xpu_available() -> bool:
     # This is defined as a function instead of a constant to avoid circular imports, because `lightning_xpu`