BC break in 5.3.3 with Nextcloud 28 and older

[nickvergessen]

• The change to the public share dav API v2 broke compatibility with older versions: refactor: @nextcloud/files is now aware of public shares also now have @nextcloud/sharing #1361
• This should have therefore resulted in a 6.0 release.

I would therefore suggest to do the following:

1. Branch of 5.3.5 as stable5
2. Tag master/main as 6.0.0
3. On stable5 revert the API change
4. Release 5.3.6 and put it into stable28 of server: [stable28] fix(sharing): Pin @nextcloud/dialogs to a version that doesn't use Nextcloud 29 APIs nextcloud/server#47271

@ShGKme @susnux Sounds like the best option to me?