Bump site-shared from 0e1ffdd to 90c64a9 (#10345)

Bumps [site-shared](https://github.com/dart-lang/site-shared) from
`0e1ffdd` to `90c64a9`.
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/dart-lang/site-shared/commit/90c64a9b0736d350f439bfb4a0baf225a3908249"><code>90c64a9</code></a>
Update inject script to account for sender (<a
href="https://github.com/dart-lang/site-shared/issues/211">#211</a>)</li>
<li>See full diff in <a
href="https://github.com/dart-lang/site-shared/compare/0e1ffdd593cfc56bd25fb9e0a5b84c5e573a7aa3...90c64a9b0736d350f439bfb4a0baf225a3908249">compare
view</a></li>
</ul>
</details>
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