[BUG] MediatR - Startups issues

[Kallie]

Describe the bug
Compile time issue with registering MediatR when nuget update MediatR, no PR

Files affected:
FSH.WebApi.Infrastructure => Startup.cs
FSH.WebApi.Application => Startup.cs

Change:
From .AddMediatR(assembly);
to .AddMediatR(cfg => cfg.RegisterServicesFromAssembly(Assembly.GetExecutingAssembly()));