指定したプラットフォーム用のアイコンサイズのリストを取得します
Most platforms support viewing icons in multiple sizes so Unity lets you specify multiple icon textures for each platform. Use this function to get the sizes to use for the specified platform, where each size specifies both the width and height in pixels. By default it returns all icons for a specified platform unless an IconKind value is specified. Currently only iOS supports icons which have a different kind than IconKind.Application.