Lua: Remove margins & spacing from repl

None of the output panes have margins. Makes it more similar to the
debugger log

Change-Id: Icc0a1287c88ca2d5876942b76cf4c0cec2cafc10
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/plugins/lua/luaplugin.cpp

@@ -190,6 +190,8 @@ public:
 
             // clang-format off
             m_ui = Column {
+                noMargin,
+                spacing(0),
                 m_terminal,
                 Row { prompt, inputEdit },
             }.emerge();