Checkpoint manager tooltip fix and filename tooltip change

[RTHilton]

Fix tooltips not appearing in lower checkpoint information panel Change Filename tooltip to show relative path

[mohnjiles]

This unfortunately makes it so clicking the bottom 1/3 of the model card no longer brings up the details dialog. I played around with it and found myself liking a separate ℹ️icon that could hold this & possibly other details, like

<avalonia:Icon Grid.Row="0" 
         Value="fa-solid fa-circle-info"
         HorizontalAlignment="Right"
         VerticalAlignment="Bottom"
         Width="24"
         Height="24"
         Margin="0,0,8,8"
         ZIndex="100"
         ToolTip.Tip="{Binding CheckpointFile.RelativePath}"/>

Right between the CheckBox and Button ~L552