fix: imported note shows its text twice when two people open it at the same time (#33004)

A note imported from a .md or .txt file on the Notes page and not edited since showed all of its text twice when two people opened it at the same time, and the doubled text was then saved into the note. The shared editing session is now the only place that loads the text of such a note, the same as for notes that were already edited, so it opens once for everyone. Like an edited note, it now needs the live connection to show its text.

Fixes #33002

src/lib/components/common/RichTextInput.svelte

@@ -411,7 +411,7 @@
 		});
 	}
 
-	$: if (value === null && html !== null && editor) {
+	$: if (value === null && html !== null && editor && !provider) {
 		editor.commands.setContent(html);
 	}