Fixed FrameMargin being overwritten by OnTitleBarChanged.

[Koichi-Kobayashi]

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: N/A

What is the new behavior?

• Even if you set the FrameMargin of ui:NavigationView to 0, FrameMarginDefault is always set.
• Setting FrameMarginDefault where the FrameMargin dependency property is registered works fine.

Other information