Hi Swati,
I am sorry i could not reply earlier.

Can you please remove the older code for Pm and try this

function filter_message_button_link( $link ) {
	$user_id = bp_get_member_user_id();

	if ( ! $user_id ) {
		return $link;
	}

	$link = wp_nonce_url( bp_loggedin_user_domain() . bp_get_messages_slug() . '/compose/?r=' . bp_get_member_user_login() );

	return $link;
}

add_filter( 'bp_get_send_private_message_link', 'filter_message_button_link', 1, 1 );

function display_private_message_button() {
	if ( bp_get_member_user_id() != bp_loggedin_user_id() ) {
		bp_send_message_button();
	}
}

add_action( 'bp_directory_members_item', 'display_private_message_button' );

It is working for me and should work for you too.

Please check and let me know.

You are welcome.
All the best with your project.

Regards
Brajesh