[FIX] mail: disable screen-sharing in mobile OS

This feature is not available in mobile OS at the time
of this commit [1]:

- Safari on iOS 17.5
- Chrome for Android 127
- Firefox for Android 127

Therefore the button should not be shown, otherwise it
mistakenly gives the impression that user could make
it work by enabling screen-sharing permission which
is not possible on mobile OS.

opw-4108833

[1]: https://caniuse.com/mdn-api_mediadevices_getdisplaymedia

closes odoo#177372

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

addons/mail/static/src/discuss/call/common/call_action_list.js

@@ -29,7 +29,7 @@ export class CallActionList extends Component {
             icon: "fa fa-fw fa-hand-paper-o",
             onSelect: (ev) => this.onClickRaiseHand(ev),
         });
-        if (isMobileOS) {
+        if (!isMobileOS()) {
             acts.push({
                 id: "shareScreen",
                 name: !this.rtc.state.sendScreen ? _t("Share Screen") : _t("Stop Sharing Screen"),