[web] Reduce the size of sliders

While keeping the ability to reach easily sliders, their visual size has been reduce to make them less bulky.

web-src/src/locales/de.json

@@ -367,6 +367,7 @@
     },
     "now-playing": {
       "info": "Tracks durch Auswählen aus der Bibliothek anfügen",
+      "live": "Live",
       "title": "Deine Playliste ist leer."
     },
     "playlist": {

web-src/src/locales/en.json

@@ -367,6 +367,7 @@
     },
     "now-playing": {
       "info": "Add some tracks by browsing your library",
+      "live": "Live",
       "title": "Your play queue is empty"
     },
     "playlist": {

web-src/src/locales/fr.json

@@ -367,6 +367,7 @@
     },
     "now-playing": {
       "info": "Ajoutez des pistes en parcourant votre bibliothèque",
+      "live": "En direct",
       "title": "La file d’attente est vide"
     },
     "playlist": {