Refactor record size limit extension handling

Signed-off-by: Waleed Elmelegy <waleed.elmelegy@arm.com>
diff --git a/tests/src/test_helpers/ssl_helpers.c b/tests/src/test_helpers/ssl_helpers.c
index d02d305..3d8937d 100644
--- a/tests/src/test_helpers/ssl_helpers.c
+++ b/tests/src/test_helpers/ssl_helpers.c
@@ -1776,6 +1776,10 @@
     }
 #endif /* MBEDTLS_SSL_CLI_C */
 
+#if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT)
+    session->record_size_limit = 2048;
+#endif
+
     return 0;
 }
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */