[OCM][Test Suite] ownCloud cannot share via public link to Nextcloud

[MahdiBaghbani]

Sharing via public link flow from ownCloud to Nextcloud results in an error.

ownCloud version 10.14.0
Nextcloud version 27.1.10

Steps to reproduce:

1. log into ownCloud, and create a public link for a file.
2. open Nextcloud in another tab and log in.
3. browse to the public link.
4. from the top right menu open add to your server, enter the Nextcloud instance URL, and hit enter.
5. on Nextcloud accept the share, and see the below error:

Note:
If you don't log into Nextcloud first (skip 2nd step), the accept share dialogue won't come up and the share will fail silently without an error.

[MahdiBaghbani]

Nextcloud v28 shows the dialogue to accept the share but won't show any error afterward and won't show the shared file.