fix: Incorrect font icon size conversion to device pixels.

[CatchABus]

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What is the current behavior?

Since NS 6, font icons used with Image, ActionItem, and few more elements have bad sizing between the 2 platforms.
It seems there's been a mistake since the implementation of this feature and font size is multiplied with display density 'twice'.

What is the new behavior?

Font icons used with Image, ActionItem, and few more elements will have proper size in both platforms.
Note: In iOS, there was a pixel conversion that was wrong and also didn't run so it was dead and was consequently removed.

Fixes #8391.