Bug: `<link rel="preload" as="font" ...>` in RSC gets duplicated in SSR html

[hi-ogawa]

React version: since 19.2.0

Steps To Reproduce

Created a PR with a test case as a reproduction in #35890

Initially reported on Waku wakujs/waku#1964 (comment). It doesn't reproduce on 19.1. It reproduces from 19.2 and latest canary.

The current behavior

<link rel="preload" as="font" ... /> appears twice in SSR html

The expected behavior

<link rel="preload" as="font" .../> appears once in SSR html