lexical: Bug: `$getSelectionStyleValueForProperty(selection, 'font-size')` not updating correctly

When using $getSelectionStyleValueForProperty(selection, 'font-size'), it does not seem to update if user changes font size on some text which has previously modified its font size. The font-family property also exhibits the same behavior.

Lexical version: 0.10.0

Steps To Reproduce

This can be reproduced in the https://playground.lexical.dev/:

1. Open lexical playground
2. Change font size for some text
3. Click away from the text
4. Highlight that same text again, and change the font size

I’ve also created a sandbox, see FontSizePlugin: https://codesandbox.io/s/dazzling-visvesvaraya-8pjcv5

Repro in sandbox by:

1. Type some text and highlight it
2. Change font size to 24px
3. Deselect text and reselect
4. Change font size to 48px

See that the text font size does change, but the getSelectionStyleValueForProperty result still says ‘24px’.

The current behavior

Toolbar does not update, but text font size does change. getSelectionStyleValueForProperty seems to still return the original value.

The expected behavior

getSelectionStyleValueForProperty will return the new font size, so that the toolbar can update to new font size.

This only happens for text that has font size changed, the initial change from no font-size to some value does seem to update correctly.