fix: Fix error when viewing current version

[juliusknorr]

Noticed in text cypress tests:

Steps to reproduce:

• Open the version sidebar
• Click on current version

Before this change we had an error thrown:

SyntaxError: JSON.parse: unexpected end of data at line 1 column 1 of the JSON data
    ee viewer-main.mjs:2
    canDownload viewer-main.mjs:8
    get logger-CYBBkF-8.chunk.mjs:2
    evaluate logger-CYBBkF-8.chunk.mjs:2
    Il logger-CYBBkF-8.chunk.mjs:2

Honestly I'm not sure where exactly to fix this best, but this seemed like the smallest change that wouldn't cause further side effects.

Viewer previously assumed a string for the share attributes however the fileInfo that the files app passes along through the version sidebar is holding an array as the JSON string is parsed in https://github.com/nextcloud/server/blob/d537050f19b264f96d86a564770835ae36ab9add/core/src/files/client.js#L398-L408

[susnux]

Really would love a new version using our classes from @nextcloud/files instead of FileInfo but until then this is good :)

[juliusknorr]

/compile