Show votes cast for undisclosed polls

[jeffrson]

Coming here via the issue selection form - this is essentially the same as element-hq/element-web#24875 but for Android.

Objective is to view how many votes have been cast for undisclosed polls before the poll is finished.

This is done already in iOS app and it seems very useful, to estimate whether the poll will be successful at all and could possibly be ended prematurely. It may be realized similarly to iOS Swift implementation. Although I don't know which data have to be requested, it should be possible since we can see this feature working for the same poll.