Update edit icon to support iOS

Replace menu_edit.png with edit_pencil.png in Compose Multiplatform

menu_edit.png was not displaying on iOS and I don't know why! Replacing it with another pencil icon .png fixes the issue.

Open source icons/edit_pencil.png edit icon by Icons8, found at https://icons8.com/icon/42449/edit

Tested on iOS, Android and JVM Mac

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