ocis migrate rebuild-jsoncs3-indexes resets share acceptance state

[wkloucek]

Describe the bug

When you run ocis migrate rebuild-jsoncs3-indexes all shares will be recreated with a share acceptance state of pending

Steps to reproduce

Steps to reproduce the behavior:

1. create shares
2. accept shares
3. ocis migrate rebuild-jsoncs3-indexes

Expected behavior

shares stay accepted

Actual behavior

shares are reset to pending

Additional context

This makes the Desktop client ask you if you want to keep or delete files that you received as shares and accepted them

[aduffeck]

Proposed fix in #7322. @butonic wdyt?