MP Lobby: increased chatbox height on standard resolution

[ci skip]

* Increase chatbox height from 25% of the screen height to 28%
* Removed remaining horizontal spacer line
* Disabled horizontal scrollbar for the game list. I had set the mode to 'auto' in order to
  reserve space for the bar should it be needed. However, I've since decreased the amount of
  content in the game listbox, rendering the chance it will be needed much less likely.

data/gui/window/lobby_main.cfg

@@ -9,7 +9,7 @@
 		definition = "default"
 
 		vertical_scrollbar_mode = "always"
-		horizontal_scrollbar_mode = "auto"
+		horizontal_scrollbar_mode = "never" # Revert to "auto" if it becomes necessary
 
 		[header]
 
@@ -876,7 +876,7 @@
 										[/column]
 									[/row]
 
-									{GUI_HORIZONTAL_SPACER_LINE}
+									#{GUI_HORIZONTAL_SPACER_LINE}
 
 									[row]
 										grow_factor = 0
@@ -887,7 +887,7 @@
 											horizontal_grow = true
 											vertical_grow = true
 
-											{GUI_FORCE_WIDGET_SIZE 0 "((screen_height * 25 / 100))" (
+											{GUI_FORCE_WIDGET_SIZE 0 "((screen_height * 28) / 100)" (
 												[chatbox]
 													id = "chat"
 												[/chatbox]