[SPARK-44424][PYTHON][CONNECT][FOLLOW-UP] Import Connect related libr…

…aries after checking dependencies

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

This PR is a followup of #42235 that fixes the Connect related import after the dependency checking.

### Why are the changes needed?

In order to show the end users a nice error message for optional dependencies instead of just saying that they were not found.

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

No, the PR has not been released out yet.

### How was this patch tested?

Manually.

Closes #42311 from HyukjinKwon/SPARK-44424-folowup.

Authored-by: Hyukjin Kwon <gurwls223@apache.org>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>

python/pyspark/sql/connect/client/core.py

@@ -20,7 +20,6 @@
     "getLogLevel",
 ]
 
-from pyspark.sql.connect.client.reattach import ExecutePlanResponseReattachableIterator
 from pyspark.sql.connect.utils import check_dependencies
 
 check_dependencies(__name__)
@@ -66,6 +65,7 @@
 from pyspark.version import __version__
 from pyspark.resource.information import ResourceInformation
 from pyspark.sql.connect.client.artifact import ArtifactManager
+from pyspark.sql.connect.client.reattach import ExecutePlanResponseReattachableIterator
 from pyspark.sql.connect.conversion import storage_level_to_proto, proto_to_storage_level
 import pyspark.sql.connect.proto as pb2
 import pyspark.sql.connect.proto.base_pb2_grpc as grpc_lib