Remove PowerTube from string

Due to the fact that PowerTube has not been consistently maintained and occasionally experiences difficulties in downloading videos.
Refer to:
razar-dev/PowerTube#57
razar-dev/PowerTube#56
razar-dev/PowerTube#54

At present, Seal and YTDLnis utilize YT-dlp, resulting in improved output.

Author: kazimmt

src/main/kotlin/app/revanced/patches/youtube/interaction/downloads/resource/patch/ExternalDownloadsResourcePatch.kt

@@ -30,7 +30,7 @@ class ExternalDownloadsResourcePatch : ResourcePatch {
                     TextPreference(
                         "revanced_external_downloader_name",
                         StringResource("revanced_external_downloader_name_title", "Downloader package name"),
-                        StringResource("revanced_external_downloader_name_summary", "Package name of your installed external downloader app, such as NewPipe or PowerTube"),
+                        StringResource("revanced_external_downloader_name_summary", "Package name of your installed external downloader app, such as NewPipe or Seal"),
                         InputType.TEXT
                     )
                 ),
@@ -50,4 +50,4 @@ class ExternalDownloadsResourcePatch : ResourcePatch {
 
         return PatchResultSuccess()
     }
-}
+}