I have found solution to get file upload path after submission.
Here you are using wromg action "gform_pre_submission".
Enstead of "gform_pre_submission_13" action use "gform_after_submission_13".
in this action, number 13 is your form id.
Refer this link for more info : https://docs.gravityforms.com/gform_after_submission/
Try Below code you will get the uploaded path after submission.
Here is my code:
function md_gform_after_submission_1( $entry, $form ) {
$upload_path = GFFormsModel::get_upload_path( $entry[ 'form_id' ] );
$upload_url = GFFormsModel::get_upload_url( $entry[ 'form_id' ] );
$filename = str_replace( $upload_url, $upload_path, $entry[ '1' ] );
echo "<div style='color:#446084;'><p><b>Your File has been stored here : </b><br/>$filename</p><div>";
}
add_action( 'gform_after_submission_1', 'md_gform_after_submission_1', 10, 2 );