Fetching data on validity time misses the last file

[jfrost-mo]

Describe the bug

When you fetch data on validity time and your data period is a factor of the analysis length then the final file will be missed. This is dur to a < check being used rather than a <= check.

How to reproduce

Steps to reproduce the behaviour:

1. Grab some data on validity time with data period = P1D and analysis length = P2D.
2. Run the workflow to fetch the data.
3. Observe in the logs that the "Retrieving paths" message only lists a single file.

Expected behaviour

The last file should be included.