fix: disabled attribute fallback (#1984)

Co-authored-by: Dominik Pschenitschni <mail@celement.de>
Reviewed-on: https://kolaente.dev/vikunja/frontend/pulls/1984
Reviewed-by: konrad <k@knt.li>
Co-authored-by: Dominik Pschenitschni <dpschen@noreply.kolaente.de>
Co-committed-by: Dominik Pschenitschni <dpschen@noreply.kolaente.de>

src/components/home/navigation.vue

@@ -94,7 +94,7 @@
 						@start="() => drag = true"
 						@end="saveListPosition"
 						handle=".handle"
-						:disabled="n.id < 0 || null"
+						:disabled="n.id < 0 || undefined"
 						tag="transition-group"
 						item-key="id"
 						:data-namespace-id="n.id"