fix: remove extra sampletime method

Author: AayushSabharwal

src/clock.jl

@@ -142,7 +142,6 @@ struct SolverStepClock <: AbstractClock
 end
 SolverStepClock() = SolverStepClock(nothing)
 
-sampletime(c) = nothing
 Base.hash(c::SolverStepClock, seed::UInt) = seed ⊻ 0x953d7b9a18874b91
 function Base.:(==)(c1::SolverStepClock, c2::SolverStepClock)
     ((c1.t === nothing || c2.t === nothing) || isequal(c1.t, c2.t))