IME visibility improvement and visible selection

[rustbasic]

IME visibility improvement and visible selection

I have made the IME indicator visible, and I have improved it to the best of our ability so far. However, we still need to continue improving it in the future.

Fix Issues: When Multiline, IME Rect is displayed far away. Fix Issues: The IME is displayed once and after it is entered, the IME is not displayed. Fix Issues: IME is not updated at the end of line when using Singleline.

• Related #4254
• Related #4269
• Related #4362

Remaining Issue : In Deferred Viewport, no 'input event' comes in handle_platform_output(). In Immediated Viewport, the ROOT's 'input event' comes in handle_platform_output().

Therefore, this is the best solution for now.