[Glitch] Fix a missing redirection on getting-started in multi column mode

Port cf170761e7 to glitch-soc

Signed-off-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/flavours/glitch/features/ui/index.jsx

@@ -191,6 +191,7 @@ class SwitchingColumnsArea extends PureComponent {
 
           {singleColumn ? <Redirect from='/deck' to='/home' exact /> : null}
           {singleColumn && pathName.startsWith('/deck/') ? <Redirect from={pathName} to={pathName.slice(5)} /> : null}
+          {!singleColumn && pathName === '/getting-started' ? <Redirect from='/getting-started' to='/deck/getting-started' exact /> : null}
 
           <WrappedRoute path='/getting-started' component={GettingStarted} content={children} />
           <WrappedRoute path='/keyboard-shortcuts' component={KeyboardShortcuts} content={children} />