Fix ssrfFilter url

[dbrain]

The recent commit to support disabling the ssrfFilter has broken url loading for non podcasts due to a copy paste error from the podcasts file. This switches the feedUrl back to the original url and makes image loading, and my kid waiting on a new audiobook, happy.

The original issue likely had a few ways to trigger it but in my scenario it was updating an audiobooks metadata and replacing the image, the error in the logs was:

[Server] Unhandled rejection: ReferenceError: feedUrl is not defined, promise: Promise { <rejected> ReferenceError: feedUrl is not defined at /snapshot/audiobookshelf-git/server/utils/fileUtils.js at new Promise (<anonymous>) at Object.downloadFile (/snapshot/audiobookshelf-git/server/utils/fileUtils.js) at /snapshot/audiobookshelf-git/server/utils/fileUtils.js at CoverManager.downloadCoverFromUrl (/snapshot/audiobookshelf-git/server/managers/CoverManager.js) at async ApiRouter.uploadCover (/snapshot/audiobookshelf-git/server/controllers/LibraryItemController.js) at async ApiRouter.updateMedia (/snapshot/audiobookshelf-git/server/controllers/LibraryItemController.js) }

After switching to my branch this error no longer occurs and the image is updated correctly.

[advplyr]

Thanks!