[Sharing NG] Replace dav property `public-link-permission` with type

## Describe the bug
When doing a `PROPFIND` on a public space, the response contains a dav property `public-link-permission` to indicate the permissions for this link. However, these permissions are being represented via permission bits, which is the old (deprecated) way of the OCS API.

Web needs this information to distinguish between the link types `view` and `uploadOnly`, since these can't be distinguished solely by the webdav permissions.

## Steps to reproduce
1. Create a public link for a folder
2. Do a `PROPFIND` to list the resources for this folder (e.g. `https://host.docker.internal:9200/remote.php/dav/public-files/CIlnOrnDLxMmPHx`)
3. Check the server response for the first resource (= the share itself)

## Expected behavior
There is a dav property that represents the link's `type`, since that's the graph property representing the permissions.

## Actual behavior
The is a dav property `public-link-permission`.

cc @rhafer