GameOfLife: Ensure BoardWidget can always contain the board

Previously, when there were more rows or columns than the BoardWidget
could contain, nothing was displayed. The BoardWidget minimum size is
now set whenever the number of rows or columns changes.

Userland/Games/GameOfLife/BoardWidget.cpp

@@ -52,6 +52,7 @@ void BoardWidget::resize_board(size_t rows, size_t columns)
         return;
     m_board->resize(rows, columns);
     m_last_cell_toggled = { rows, columns };
+    set_min_size(columns, rows);
 }
 
 void BoardWidget::set_running_timer_interval(int interval)

Userland/Games/GameOfLife/main.cpp

@@ -63,6 +63,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     board_widget_container.set_layout<GUI::VerticalBoxLayout>(GUI::Margins {}, 0);
     auto board_widget = TRY(board_widget_container.try_add<BoardWidget>(board_rows, board_columns));
     board_widget->randomize_cells();
+    board_widget->set_min_size(board_columns, board_rows);
 
     auto& statusbar = *main_widget->find_descendant_of_type_named<GUI::Statusbar>("statusbar");
     statusbar.set_text(click_tip);