Only show large Khoj favicon on web interface

- Do not want browsers to use the small, grainy favicons
- Firefox for Android does use the bigger icon, when it's the only one available
- Update svg to match the 144x144 ratio just for consistency

src/interface/web/khoj.webmanifest

@@ -7,16 +7,6 @@
             "src": "/static/assets/icons/favicon-144x144.png",
             "sizes": "144x144",
             "type": "image/png"
-        },
-        {
-            "src": "/static/assets/icons/favicon-32x32.png",
-            "sizes": "32x32",
-            "type": "image/png"
-        },
-        {
-            "src": "/static/assets/icons/favicon-16x16.png",
-            "sizes": "16x16",
-            "type": "image/png"
         }
     ],
     "theme_color": "#ffffff",