I am not a lawyer, but I interpret the following to mean you can use glyphs provided in the Apple Color Emoji font (on an Apple-branded system running macOS) to generate read-only icons to be used in the App Store (or anywhere else).
From the macOS Monterey software license agreement:
E. Fonts. Subject to the terms and conditions of this License, you may use the fonts included with the Apple Software to display and print content while running the Apple Software; however, you may only embed fonts in content if that is permitted by the embedding restrictions accompanying the font in question. These embedding restrictions can be found in the Font Book/Preview/Show Font Info panel.
An image icon to be used in the App Store would be, by my reading, embedding the font. From from the Show Font Info panel for the Apple Color Emoji font (Version 17.4d12e1):
Embedding: Preview and print embedding. This font may be embedded in documents and temporarily loaded on the remote system. Documents containing this font must be opened “read-only;” no edits can be applied to the document.
Since an icon file is a read-only document and no edits can be applied to the document, the use seems permitted.