poll [nfc]: Set vote count box's minHeight with ConstrainedBox

On devices with non-default text scaling, the fixed size vote count box
might be too short to fit in the text.  We should only set the min
height to fix that.

Signed-off-by: Zixuan James Li <[email protected]>

Author: PIG208

lib/widgets/poll.dart

@@ -76,9 +76,8 @@ class _PollWidgetState extends State<PollWidget> {
           textBaseline: localizedTextBaseline(context),
           children: [
             ConstrainedBox(
-              constraints: const BoxConstraints(minWidth: 25),
+              constraints: const BoxConstraints(minWidth: 25, minHeight: 25),
               child: Container(
-                height: 25,
                 padding: const EdgeInsets.symmetric(horizontal: 4),
                 decoration: BoxDecoration(
                   color: theme.colorPollVoteCountBackground,