ducktape: Change condition for upload check

The condition for the test checks if the number of segments uploaded is
exactly equal to one minus the local segment count. Since the max
upload interval is set we can end up uploading all segments to the
cloud (as seen in CI failures). This change adjusts the success
condition to include the case where all segments are uploaded.

tests/rptest/tests/retention_policy_test.py

@@ -473,7 +473,7 @@ def cloud_log_segment_count() -> int:
             f"Waiting for {local_seg_count - 1} segments to be uploaded to the cloud"
         )
         # Wait for everything to be uploaded to the cloud.
-        wait_until(lambda: cloud_log_segment_count() == local_seg_count - 1,
+        wait_until(lambda: cloud_log_segment_count() >= local_seg_count - 1,
                    timeout_sec=10,
                    backoff_sec=2,
                    err_msg=f"Segments not uploaded")