Fix hostname field input blocking in SCMU

[cquirosj]

Fix hostname field input blocking in ServiceControl Management Utility

Addresses part of #5190 to allow for dashes

• Management view for adding instances rules for allowed characters in hostname are incorrect #5190

Problem

The hostname fields in the ServiceControl Management Utility (SCMU) were blocking valid dash (-) characters from being typed, while allowing invalid characters like /[]|. This was caused by CheckBox controls intercepting keystrokes for nested TextBox controls in the add instance views.

Users reported that typing - would not work but typing any of /[]| does work. The only workaround was to paste the dash character from the clipboard.

Root Cause

The issue occurred because:

1. TextBox controls for hostname input were nested inside CheckBox controls in the XAML layout
2. WPF CheckBox controls intercept certain keystrokes (including dashes) for their nested content
3. This prevented users from typing dashes directly into hostname fields, requiring copy/paste workarounds

Solution

Restructured the UI layout in the add instance views to separate CheckBox and Expander controls using a Grid-based horizontal layout.

Before:

<CheckBox IsChecked="{Binding InstallErrorInstance}">
    <Expander Header="ServiceControl">
        <!-- TextBox controls nested inside CheckBox -->
        <controls:FormTextBox Header="HOST NAME" Text="{Binding ErrorHostName}" />
    </Expander>
</CheckBox>

After:

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>

    <CheckBox Grid.Column="0"
              IsChecked="{Binding InstallErrorInstance}"
              VerticalAlignment="Top"
              Margin="0,8,8,5"/>

    <Expander Grid.Column="1"
              Header="ServiceControl"
              IsEnabled="{Binding InstallErrorInstance}"
              Margin="0,5,0,5">
        <!-- TextBox controls no longer nested in CheckBox -->
        <StackPanel Visibility="{Binding InstallErrorInstance, Converter={StaticResource boolToVis}}">
            <controls:FormTextBox Header="HOST NAME" Text="{Binding ErrorHostName}" />
        </StackPanel>
    </Expander>
</Grid>