(TextInput) Removing deprecated Margin and Handle flip API

(TextInput) Removing deprecated Margin and Handle flip API

[Issue#] N/A
[Problem] N/A
[Cause] N/A
[Solution] Removing:

  /* @deprecated, use SetBoundingRectangle instead. */
  void SetSelectionHandleFlipMargin( const Vector4& margin );

  /* @deprecated, use GetBoundingRectangle instead. */
  const Vector4& GetSelectionHandleFlipMargin();

  /* @deprecated, handles always flip. Use SetBoundingRectangle */
  void EnableSelectionHandleFlip( bool toggle );

  /* @deprecated, handles always flip. Use SetBoundingRectangle */
  bool IsSelectionHandleFlipEnabled();

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