Consistently store user names in matches and requests

[nicholaschiang]

Is your feature request related to a problem? Please describe.
In order to speed up the client-side data fetching, I added a name and photo property to the Person objects that are stored in matches and requests. This way, the client only has to fetch the /api/matches endpoint once (instead of fetching partial data and then calling the /api/users/[id] endpoint to get the user's data). This, however, led to data duplication (that is common in NoSQL schema-less databases like Firestore) which can result in inaccurate information (i.e. no single source of truth).

For example, the name properties of some documents are the truncated versions (i.e. "John D." instead of "John Doe"). We want to be consistent in our decisions to truncate data, and this was not intentional (and thus isn't consistent).

Describe the solution you'd like
Once #128 is fixed, ensure that those name properties aren't truncated when the POST /api/matches and PUT /api/matches/[id] endpoints are called.

Additional context
Related to 528fa026.