fix(server): flaky metadata tests

[uhthomas]

Description

Dates on the asset factory use the current time, and they are usually all the same time, but may occasionally be a millisecond out. This behaviour hid the fact that some tests were asserting against the wrong field, and would flake.

We can resolve this by ensuring that each date on a test asset is unique.

How Has This Been Tested?

Ran the tests.

Checklist:

• I have carefully read CONTRIBUTING.md
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if applicable
• I have no unrelated changes in the PR.
• I have confirmed that any new dependencies are strictly necessary.
• I have written tests for new code (if applicable)
• I have followed naming conventions/patterns in the surrounding code
• All code in src/services/ uses repositories implementations for database calls, filesystem operations, etc.
• All code in src/repositories/ is pretty basic/simple and does not have any immich specific logic (that belongs in src/services/)

Please describe to which degree, if any, an LLM was used in creating this pull request.

N/A

[danieldietzler]

I am wondering if we'd want some sort of randomization in the newDate instead. I suppose this is fine though

[uhthomas]

Maybe, though it might be weird to have an updated at before a created at, so this ordering kinda makes sense?