credentials don't show, if vault has shared credentials

[budachst]

Describe the bug
If a passman vault has shared credentials, passman-ios will load the credentials, at least it seems so, since the waiting indicator spins, and then return an empty list, where no credentials are displayed.

To Reproduce
Steps to reproduce the behavior:

1. Go to a credential in your passman vault on your mac or pc - not iOS device
2. Select sharing from the options of that credential and share it with some other NC user account
3. Switch to your iOS device and refresh passman-ios
4. The vault will be displayed as if no credential is available

Expected behavior
The vault's credentials should be displayed

Screenshots
If applicable, add screenshots to help explain your problem.

Smartphone (please complete the following information):

• Device: iPhone X
• OS: iOS 12
• Passman Version: 2.1.4