Update `time_updated` with `PUT` endpoints

[AdamAWiener]

Description

When the PUT /encounters and PUT /persons endpoints are called, we need to update the time_updated field of the modified item so that we can track recently changed items and display them in order on the front end.

Acceptance Criteria

• [ ] time_updated updates to current time when PUT /encounters/:id or PUT /persons/:id are called successfully.

Implementation details

This will be a change related to the respective endpoints' controller files.

Testing notes

Please ensure all existing tests pass!

[hajineats]

Approved!

[jimwang6012]

LGTM!