Do not add Transfer-Encoding chunked explicitly in object storage

The urllib3 adds header automatically in lovercase, avoid adding 2 headers.

Add Content-Type header instead like it is done in image service.

Related-Prod: PRODX-22472
Change-Id: I27329fd367beb912c9d8f6a81af832058887980c
diff --git a/tempest/api/object_storage/test_object_services.py b/tempest/api/object_storage/test_object_services.py
index 2823185..268e098 100644
--- a/tempest/api/object_storage/test_object_services.py
+++ b/tempest/api/object_storage/test_object_services.py
@@ -187,7 +187,7 @@
         """Test creating object with transfer_encoding"""
         object_name = data_utils.rand_name(name='TestObject')
         data = data_utils.random_bytes(1024)
-        headers = {'Transfer-Encoding': 'chunked'}
+        headers = {'Content-Type': 'application/octet-stream'}
         resp, _ = self.object_client.create_object(
             self.container_name,
             object_name,