chore: remove configuration note from updates preferences

Remove the explanation text about configuring appcast URL and EdDSA key.
This is configuration for developers, not end users.

Sources/Views/PreferencesView.swift

@@ -252,11 +252,6 @@ private struct UpdatesPreferencesView: View {
                 Label("Check for Updates Now", systemImage: "sparkles")
             }
 
-            Text("Updates are delivered via Sparkle. Configure your appcast URL and public EdDSA key in Info.plist (keys `SUFeedURL` and `SUPublicEDKey`).")
-                .font(.caption)
-                .foregroundColor(.secondary)
-                .padding(.top, 4)
-
             Spacer()
         }
         .toggleStyle(.switch)