Fix Controls bug

[Maklith]

Pull request type

Please check the type of change your PR introduces:

• Update
• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes

What is the current behavior?

Issue Number: #635

What is the new behavior?

1. Fix LeftFluentNavigationViewItemTemplate content fontsize binding
   
   

2. Fix TextBox Icon size,Add two properties to define the icon size and width of the TextBoxClearButton
   Also make icon and the TextBoxClearButton at the center
   
   
   
   It should be like this
   
   but it is like this
   
   It only works when I hot reload the binding, I don't know how to fix this

3. Fix Expander Header fontsize
   

Other information

• There are some bugs that need help

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[cla-bot]

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[FluentSk8]

Is this update released in 3.0.0-preview10? Since this update I can no longer change the FontSize of MenuItems and so they are too big to be displayed if they are longer than 9 characters.

[FluentSk8]

Sorry, can be solved by this. So everything okay.

                <ui:NavigationView.FooterMenuItems>
                    <ui:NavigationViewItem>
                        <ui:NavigationViewItem.Icon>
                            <ui:SymbolIcon Symbol="Settings28" />
                        </ui:NavigationViewItem.Icon>

                        <ui:NavigationViewItem.Content>
                            <TextBlock FontSize="8"
                                       Text="Einstellungen" />
                        </ui:NavigationViewItem.Content>
                    </ui:NavigationViewItem>
                </ui:NavigationView.FooterMenuItems>

[Maklith]

Sorry, can be solved by this. So everything okay.抱歉，可以这样解决。所以一切都好。

                <ui:NavigationView.FooterMenuItems>
                    <ui:NavigationViewItem>
                        <ui:NavigationViewItem.Icon>
                            <ui:SymbolIcon Symbol="Settings28" />
                        </ui:NavigationViewItem.Icon>

                        <ui:NavigationViewItem.Content>
                            <TextBlock FontSize="8"
                                       Text="Einstellungen" />
                        </ui:NavigationViewItem.Content>
                    </ui:NavigationViewItem>
                </ui:NavigationView.FooterMenuItems>

this is not a problem caused by this PR, but in a recent update (from someone else), the fact that the FontSize attribute for many controls is invalid if the Content/Header is set directly to the string