refactor(server): use exiftool for file date metadata

[mertalev]

Description

There are two redundant stat calls in metadata extraction that can instead use the exiftool output (tags starting with File are from the file system). Besides generally less file IO, it avoids taking up a thread (or waiting to acquire one) in the all-too-limited libuv threadpool. Based on #16450, which should be merged first.

I tested locally and it works as expected. However, there are cases in the library E2E tests where the tags are undefined. I don't know why this is. The PR falls back to calling .stat in this case to handle this.

This is the last of the PRs split off from #14277.

[zackpollard]

Throwing copilot reviewer at this as a test

[alextran1502]

Can you help resolve conflict? I can help with another round of testing

[mertalev]

Conflicts are resolved