[SPARK-48232][PYTHON][TESTS] Fix 'pyspark.sql.tests.connect.test_conn…

…ect_session' in Python 3.12 build

### What changes were proposed in this pull request?

This PR avoids importing `scipy.sparse` directly which hangs indeterministically specifically with Python 3.12

### Why are the changes needed?

To fix the build with Python 3.12 https://github.com/apache/spark/actions/runs/9022174253/job/24804919747
I was able to reproduce this in my local but a bit indeterministic.

### Does this PR introduce _any_ user-facing change?

No, test-only.

### How was this patch tested?

Manually tested in my local.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes apache#46522 from HyukjinKwon/SPARK-48232.

Authored-by: Hyukjin Kwon <[email protected]>
Signed-off-by: Hyukjin Kwon <[email protected]>

python/pyspark/testing/utils.py

@@ -38,7 +38,7 @@
 have_scipy = False
 have_numpy = False
 try:
-    import scipy.sparse  # noqa: F401
+    import scipy  # noqa: F401
 
     have_scipy = True
 except ImportError: