[FIX] im_livechat: make external livechat work with only im_livechat

Follow-up of https://github.com/odoo/odoo/pull/92786

Commit above make external livechat not working due to
`info['available']` being `True`, and `True` is not
a valid javascript keyword. The correct value is `true`,
starting with a smaller case.

closes odoo/odoo#94711

Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>

addons/im_livechat/views/im_livechat_channel_templates.xml

@@ -93,7 +93,7 @@
                 window.addEventListener('load', function () {
                     odoo.define('im_livechat.loaderData', function() {
                         return {
-                            isAvailable: <t t-out="info['available']"/>,
+                            isAvailable: <t t-out="'true' if info['available'] else 'false'"/>,
                             serverUrl: "<t t-out="info['server_url']"/>",
                             options: <t t-out="json.dumps(info.get('options', {}))"/>,
                         };