Minor extension repo enhancements

- Shortcut to settings from extensions tab
- Don't show error toast anymore if nothing's loaded
- Ability to copy extension repo URL to clipboard

app/src/main/java/eu/kanade/tachiyomi/extension/api/ExtensionApi.kt

@@ -35,15 +35,7 @@ internal class ExtensionApi {
 
     suspend fun findExtensions(): List<Extension.Available> {
         return withIOContext {
-            val extensions = sourcePreferences.extensionRepos().get().flatMap { getExtensions(it) }
-
-            // Sanity check - a small number of extensions probably means something broke
-            // with the repo generator
-            if (extensions.isEmpty()) {
-                throw Exception()
-            }
-
-            extensions
+            sourcePreferences.extensionRepos().get().flatMap { getExtensions(it) }
         }
     }