Newer `slstr-wst` and `olci-wfr` Items missing assets

**Describe the bug**
Newer `slstr-wst` and `olci-wfr` archives contain a `browse.jpg` file and an`EOPMetadata.xml` file. They should be included in the Item assets.

**To reproduce**
Create an `slstr-wst` or `olci-wfr` Item from a SEN3 archive from the past year or so (which will contain the additional files).