Show unique displayname context in the user share list entries

apps/files_sharing/lib/Controller/ShareAPIController.php

apps/files_sharing/src/components/SharingEntry.vue

apps/files_sharing/src/components/SharingEntrySimple.vue

apps/files_sharing/src/mixins/SharesMixin.js

apps/files_sharing/src/models/Share.js

apps/files_sharing/src/views/SharingList.vue

...files_sharing/tests/Controller/ShareAPIControllerTest.php