Change extension repo to extension store and add support for newer extension index format (#3349)

app/src/main/java/eu/kanade/tachiyomi/extension/ExtensionManager.kt

@@ -204,11 +204,11 @@ class ExtensionManager(
                 if (extension.hasUpdate != hasUpdate) {
                     installedExtensionsMap[pkgName] = extension.copy(
                         hasUpdate = hasUpdate,
-                        repoUrl = availableExt.repoUrl,
+                        store = availableExt.store,
                     )
                 } else {
                     installedExtensionsMap[pkgName] = extension.copy(
-                        repoUrl = availableExt.repoUrl,
+                        store = availableExt.store,
                     )
                 }
                 changed = true
@@ -228,7 +228,7 @@ class ExtensionManager(
      * @param extension The extension to be installed.
      */
     fun installExtension(extension: Extension.Available): Flow<InstallStep> {
-        return installer.downloadAndInstall(api.getApkUrl(extension), extension)
+        return installer.downloadAndInstall(extension.apkUrl, extension)
     }
 
     /**