[Webservice] Remove extra slash from reports-folder config

Description

@schmidtp noticed report folders in the logs with double slashes:

 --report-to /gpfs/exfel/exp/HED/202421/p008096/usr/Reports/r0157//HED_IA1_JF500K2_correct_008096_r0157_240605_063442_544141

This works, but it might make it harder to search the logs, for instance.

How Has This Been Tested?

I've checked both the places in the code that use this config value, and they don't need a trailing slash. The equivalent config for darks already doesn't have it.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Reviewers

@schmidtp