Use some() instead of findIndex() !== -1

Signed-off-by: Raimund Schlüßler <raimund.schluessler@mailbox.org>

src/components/NcAppSidebar/NcAppSidebarTabs.vue

@@ -200,7 +200,7 @@ export default {
 		 */
 		updateActive() {
 			this.activeTab = this.active
-			&& this.tabs.findIndex(tab => tab.id === this.active) !== -1
+			&& this.tabs.some(tab => tab.id === this.active)
 				? this.active
 				: this.tabs.length > 0
 					? this.tabs[0].id