Update the Firefox launcher.

With changes from the flatpak.

.local/share/applications/org.mozilla.firefox.desktop

@@ -50,7 +50,7 @@ MimeType=text/html;text/xml;application/xhtml+xml;application/vnd.mozilla.xul+xm
 StartupNotify=true
 Categories=Network;WebBrowser;
 Keywords=web;browser;internet;
-Actions=new-window;new-private-window;
+Actions=new-window;new-private-window;profile-manager-window;
 X-Flatpak=org.mozilla.firefox
 StartupWMClass = Firefox
 
@@ -269,3 +269,8 @@ Name[xh]=Ifestile yangasese entsha
 Name[zh-CN]=新建隐私浏览窗口
 Name[zh-TW]=新增隱私視窗
 Exec=/usr/bin/flatpak run --branch=stable --arch=x86_64 --command=firefox --file-forwarding org.mozilla.firefox --private-window @@u %u @@
+
+[Desktop Action profile-manager-window]
+Name=Open the Profile Manager
+Name[cs]=Správa profilů
+Exec=/usr/bin/flatpak run --branch=stable --arch=x86_64 --command=firefox org.mozilla.firefox --ProfileManager