chore: enhance site.webmanifest in firefox (#4828)

Signed-off-by: Kevin <16837578+KevinStaude@users.noreply.github.com>

web/public/site.webmanifest

 {
   "name": "Memos",
-  "short_name": "",
+  "short_name": "Memos",
   "icons": [
     { "src": "/android-chrome-192x192.png", "sizes": "192x192", "type": "image/png" },
     { "src": "/android-chrome-512x512.png", "sizes": "512x512", "type": "image/png" }