fix erroring PlotData2D(sol) calls

this is weird - Julia is loading SciMLBase v2.50.5 for me locally, which includes a `discType` parameter.

https://github.com/SciML/SciMLBase.jl/blob/12f30308a4f4959dd6bbf97efc1f600621546cf4/src/solutions/ode_solutions.jl#L108C65-L109

However, I don't think any StartUpDG changes should have triggered this, so I'm not sure why these tests are failing now

src/visualization/types.jl

@@ -5,8 +5,8 @@
 #
 # Note: This is an experimental feature and may be changed in future releases without notice.
 #! format: off
-const TrixiODESolution = Union{ODESolution{T, N, uType, uType2, DType, tType, rateType, P} where
-    {T, N, uType, uType2, DType, tType, rateType, P<:ODEProblem{uType_, tType_, isinplace, P_, F_} where
+const TrixiODESolution = Union{ODESolution{T, N, uType, uType2, DType, tType, rateType, discType, P} where
+    {T, N, uType, uType2, DType, tType, rateType, discType, P<:ODEProblem{uType_, tType_, isinplace, P_, F_} where
      {uType_, tType_, isinplace, P_<:AbstractSemidiscretization, F_}}, TimeIntegratorSolution}
 #! format: on