Fix: remove accidental pyspark dependency added in ruff refactor (#2587)

Author: georgesittas

sqlmesh/core/snapshot/evaluator.py

@@ -30,7 +30,6 @@
 from functools import reduce
 
 import pandas as pd
-from pyspark.sql.dataframe import DataFrame as PySparkDataFrame
 from sqlglot import exp, select
 from sqlglot.executor import execute
 
@@ -544,10 +543,13 @@ def apply(query_or_df: QueryOrDF, index: int = 0) -> None:
 
             if limit is not None:
                 query_or_df = next(queries_or_dfs)
-                if isinstance(query_or_df, PySparkDataFrame):
-                    return query_or_df.limit(limit)
                 if isinstance(query_or_df, pd.DataFrame):
                     return query_or_df.head(limit)
+                if not isinstance(query_or_df, exp.Expression):
+                    # We assume that if this branch is reached, `query_or_df` is a pyspark dataframe,
+                    # so we use `limit` instead of `head` to get back a dataframe instead of List[Row]
+                    # https://spark.apache.org/docs/3.1.1/api/python/reference/api/pyspark.sql.DataFrame.head.html#pyspark.sql.DataFrame.head
+                    return query_or_df.limit(limit)
 
                 assert isinstance(query_or_df, exp.Query)