Fix media tab not loading Thumbnails for images on server only

[camillo-positano]

• [x ] Tests written, or not not needed

Hello i've had this issue for a long time and wanted to fix it.

The problem i found was that the cache manager never requested the server for a thumbnail because the condition to do so was never true. This caused that all my remote photos thumbnails were the default thumbnail image.

From what i understand if there is not a preview but there is a remote id it should ask the server for a thumbnail.

This never happened because of an && instead of an ||.

I also had to set updateThumbnailNeeded to false when it finished otherwise it entered a loop because it kept passing the validation: if (thumbnail == null || file.isUpdateThumbnailNeeded()).

Regarding test i didn't really understand where and how to test this functionality because, in case of an integration test, i need a server to call.

I would be more than happy to add a test if some kind soul could give me a little help xD <3

[github-actions]

Hello there,
Thank you so much for taking the time and effort to create a pull request to our Nextcloud project.

We hope that the review process is going smooth and is helpful for you. We want to ensure your pull request is reviewed to your satisfaction. If you have a moment, our community management team would very much appreciate your feedback on your experience with this PR review process.

Your feedback is valuable to us as we continuously strive to improve our community developer experience. Please take a moment to complete our short survey by clicking on the following link: https://cloud.nextcloud.com/apps/forms/s/i9Ago4EQRZ7TWxjfmeEpPkf6

Thank you for contributing to Nextcloud and we hope to hear from you soon!

(If you believe you should not receive this message, you can add yourself to the blocklist.)