I don't think this is necessarily a final solution (as this means all
HUD elements are adding overhead even when not visible), but this will
make the implementations much easier for the time being.
I've checked and can't notice any perceivable overhead in profiling so
we should be fine for now.
This is not required due to `createFileInfos` always being run before we
get to this point (I believe this was added after the initial code to
check existence was added).
This flow is covered in
`BeatmapImportTests.TestImportThenReimportAfterMissingFiles`, which
still passes with the change.
While this check isn't doing any harm, as I'm going through the flow for
import-skipping, less checks are appreciated.