Fix usages of uSES with missing getServerSnapshot

[jsnajdr]

Fixes #60924. The useSyncExternalStore call that I introduced in #60879 was missing the third getServerSnapshot parameter used in SSR mode. That triggered an error:

Internal error: Error: Missing getServerSnapshot, which is required for server-rendered content.

I also found another instance of the same bug in the PluginArea component.

[github-actions]

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Co-authored-by: jsnajdr <[email protected]>
Co-authored-by: Mamaduka <[email protected]>
Co-authored-by: diegohaz <[email protected]>

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[Mamaduka]

Thank you, @jsnajdr!