fix: hide collaborator list on mobile if empty (#2938)

Co-authored-by: Lipis <lipiridis@gmail.com>

src/components/LayerUI.tsx

@@ -513,7 +513,8 @@ const LayerUI = ({
               "transition-right": zenModeEnabled,
             })}
           >
-            {Array.from(appState.collaborators)
+            {appState.collaborators.size > 0 &&
+              Array.from(appState.collaborators)
                 // Collaborator is either not initialized or is actually the current user.
                 .filter(([_, client]) => Object.keys(client).length !== 0)
                 .map(([clientId, client]) => (

src/components/MobileMenu.tsx

@@ -152,6 +152,7 @@ export const MobileMenu = ({
                 <Stack.Col gap={4}>
                   {renderCanvasActions()}
                   {renderCustomFooter?.(true)}
+                  {appState.collaborators.size > 0 && (
                     <fieldset>
                       <legend>{t("labels.collaborators")}</legend>
                       <UserList mobile>
@@ -170,6 +171,7 @@ export const MobileMenu = ({
                           ))}
                       </UserList>
                     </fieldset>
+                  )}
                 </Stack.Col>
               </div>
             </Section>