Sorting hat package creates identity with missing information when merged and unmerged

When we merge one profile with another, we call sortinghat.api.merge_unique_identities (https://github.com/LF-Engineering/dev-analytics-sortinghat-api/blob/master/app/apis/profiles/apis.py#L190), with a `from` and `to` uuid. The `from` identity is then deleted and added into the `to` identity.

Afterwards, if we unmerge that identity from the `to` identity, for which we use sortinghat.api.move_identity (https://github.com/LF-Engineering/dev-analytics-sortinghat-api/blob/master/app/apis/profiles/apis.py#L269), the `from` identity that was earlier deleted is recreated but it will be missing name, email and other personal details information it previously had.