Android: Route DolphinBar Balance Board to the Balance Board slot

WiimoteScannerAndroid::FindAttachedWiimotes() added every device
connected through the DolphinBar to the Wii Remote results, with a
TODO noting that balance boards were not differentiated. As a result,
a Wii Balance Board connected through the DolphinBar was always
assigned to a Wii Remote slot (Player 1), and games that request a
Balance Board never detected it.

Use Wiimote::IsBalanceBoard() to route balance boards into the
balance_boards results, matching the Linux and Windows scanner
backends. Tested on an AYN Thor (Android 13) with a Mayflash
DolphinBar in Mode 4 running Wii Fit Plus: the board is now detected
in the Balance Board slot.

Source/Core/Core/HW/WiimoteReal/IOAndroid.cpp

@@ -46,10 +46,12 @@ auto WiimoteScannerAndroid::FindAttachedWiimotes() -> FindResults
       if (!wiimote->ConnectInternal())
         continue;
 
-      // TODO: We make no attempt to differentiate balance boards here.
-      // wiimote->IsBalanceBoard() would probably be enough to do that.
-
-      results.wii_remotes.emplace_back(std::move(wiimote));
+      // Differentiate balance boards so they are routed to the balance
+      // board results rather than being treated as a regular Wii Remote.
+      if (wiimote->IsBalanceBoard())
+        results.balance_boards.emplace_back(std::move(wiimote));
+      else
+        results.wii_remotes.emplace_back(std::move(wiimote));
     }
   }