how to change leaflet attribution

I’m using Leaflet with Esri.WorldShadedRelief.
As far as I understand I need to set the Leaflet attribution as follows:
‘Tiles © Esri — Source: Esri’
How ever when I try to set it up, it doesn’t change.
I’m using AngularJS.

My Leaflet defaults:

defaults: {
    keyboard: false,
    dragging: false,
    worldCopyJump: false,
    doubleClickZoom: false,
    scrollWheelZoom: false,
    tap: false,
    touchZoom: false,
    zoomControl: false,
    zoomsliderControl: false,
    zoomControlPosition: 'topleft',
    attributionControl: true,
    attribution: 'Tiles © Esri — Source: Esri',
    controls: {
        layers: {
            visible: true,
            position: 'topright',
            collapsed: true,
tiles: {
    url: '{z}/{y}/{x}'

Source: AngularJS