Qt: Fix a couple of theme switching glitches

src/duckstation-qt/setupwizarddialog.ui

@@ -45,7 +45,7 @@
         <number>0</number>
        </property>
        <item>
-        <widget class="QLabel" name="label_2">
+        <widget class="QLabel" name="introLabel">
          <property name="text">
           <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;h1 style=&quot; margin-top:18px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;&quot;&gt;&lt;span style=&quot; font-size:xx-large; font-weight:700;&quot;&gt;Welcome to DuckStation!&lt;/span&gt;&lt;/h1&gt;&lt;p&gt;This wizard will help guide you through the configuration steps required to use the application. It is recommended if this is your first time installing DuckStation that you view the setup guide at &lt;a href=&quot;https://github.com/stenzek/duckstation#downloading-and-running&quot;&gt;&lt;span style=&quot; text-decoration: underline; color:#0000ff;&quot;&gt;https://github.com/stenzek/duckstation#downloading-and-running&lt;/span&gt;&lt;/a&gt;.&lt;/p&gt;&lt;p&gt;By default, DuckStation will connect to the server at &lt;a href=&quot;https://github.com/&quot;&gt;&lt;span style=&quot; text-decoration: underline; color:#0000ff;&quot;&gt;github.com&lt;/span&gt;&lt;/a&gt; to check for updates, and if available and confirmed, download update packages from &lt;a href=&quot;https://github.com/&quot;&gt;&lt;span style=&quot; text-decoration: underline; color:#0000ff;&quot;&gt;github.com&lt;/span&gt;&lt;/a&gt;. If you do not wish for DuckStation to make any network connections on startup, you should uncheck the Automatic Updates option now. The Automatic Update setting can be changed later at any time in Interface Settings.&lt;/p&gt;&lt;p&gt;Please choose a language and theme to begin.&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
          </property>