Fix scan reversediff issue

[seabbs]

This currently prevents benchmarks being run on Renewal. Any fix should check these and integrate them into the wider benchmarking backend.

Rt-without-renewal/benchmark/bench/EpiInfModels/Renewal.jl

Line 1 in eacfd57

# Error: ArgumentError: Converting an instance of ReverseDiff.TrackedReal{Float64, Float64, Nothing} to Float64 is not defined. Please use `ReverseDiff.value` instead.

[SamuelBrand1]

I'm a bit confused by this one, because if we have hard-typed a variable somewhere as Float64 when ReverseDiff needed to overload as TrackedReal we should have code failure in other areas (e.g. the getting started example(s))

[seabbs]

Yes its a poser. I haven't inspected the guts of what TuringBenchmarks is doing so perhaps there is some difference vs what we are doing elsewhere.

[seabbs]

Closing as not doing due to #384