Reword instance-specific account settings, apply clang-format

Signed-off-by: Aaron <10217842+byteduck@users.noreply.github.com>

launcher/ui/pages/instance/InstanceSettingsPage.ui

@@ -611,7 +611,7 @@
        <item>
         <widget class="QGroupBox" name="instanceAccountGroupBox">
          <property name="title">
-          <string>Set a default account to use with this instance</string>
+          <string>Override default account</string>
          </property>
          <property name="checkable">
           <bool>true</bool>