Remove "opened" in timestamp

Author: donokuda

src/GitHub.VisualStudio/UI/Views/Controls/PullRequestListItem.xaml

@@ -131,8 +131,7 @@
                    TextTrimming="CharacterEllipsis"
                    Foreground="{DynamicResource GitHubVsGrayText}">
           <TextBlock.Text>
-            <MultiBinding StringFormat="{} {0} {1} {2} {3}">
-              <Binding Source="{x:Static i18n:Resources.prOpenedText}" />
+            <MultiBinding StringFormat="{} {0} {1} {2}">
               <Binding Converter="{StaticResource DurationToStringConverter}" Path="UpdatedAt" />
               <Binding Source="{x:Static i18n:Resources.prOpenedByText}" />
               <Binding Path="Author.Login" />