fix: fix downstream indexing tests

[AayushSabharwal]

Checklist

• Appropriate tests were added
• Any code changes were done in a way that does not break public API
• All documentation related to code changes were updated
• The new code follows the
  contributor guidelines, in particular the SciML Style Guide and
  COLPRAC.
• Any new documentation only uses public API

Additional context

Add any other context about the problem here.

[AayushSabharwal]

This is good to go, SciMLBase Downstream CI passes locally. It fails here because for some reason it's not using this branch of MTK

[SebastianM-C]

MWE for bug in BatchedInterface with vector parameters

using SymbolicIndexingInterface
using ModelingToolkit
using ModelingToolkit: t_nounits as t, D_nounits as D

function make_sys1()
    @parameters p1=0.5 [tunable = true] (p23[1:2]=[1, 3.0]) [tunable = true] p4=3 * p1 [tunable = false] y0=1.2 [tunable = true]
    @variables x(t)=2p1 y(t)=y0 z(t)=x + y

    eqs = [D(x) ~ p1 * x - p23[1] * x * y
           D(y) ~ -p23[2] * y + p4 * x * y
           z ~ x + y]

    structural_simplify(complete(ODESystem(eqs, t, tspan = (0, 3.0), name = :sys)))
end

function make_sys2()
    @parameters p1=1 [tunable = false] (p23[1:2]=[1, 3.0]) [tunable = true] p4=3 * p1
    @variables x(t)=2 * p1 y(t)=0.2 z(t)

    eqs = [D(x) ~ p1 * x - p23[1] * x * y
           D(y) ~ -p23[2] * y + p4 * x * y
           z ~ x + y]

    structural_simplify(complete(ODESystem(eqs, t, tspan = (0, 3.0), name = :sys)))
end

sys1 = make_sys1()
sys2 = make_sys2()

prob1 = ODEProblem(sys1, [sys1.p23 => [2, 4.0]])
prob2 = ODEProblem(sys2, [sys2.p1 => 2.0])

bi = BatchedInterface((prob1, [sys2.p1, sys1.p23]))
param_getter = getu(bi)

param_getter(prob1, prob2)

gives

ERROR: ArgumentError: invalid index: (3, 4, 1) of type Tuple{Int64, Int64, Int64}
Stacktrace:
  [1] to_index(i::Tuple{Int64, Int64, Int64})
    @ Base ./indices.jl:300
  [2] to_index(A::Vector{Float64}, i::Tuple{Int64, Int64, Int64})
    @ Base ./indices.jl:277
  [3] _to_indices1(A::Vector{Float64}, inds::Tuple{Base.OneTo{Int64}}, I1::Tuple{Int64, Int64, Int64})
    @ Base ./indices.jl:359
  [4] to_indices
    @ ./indices.jl:354 [inlined]
  [5] to_indices
    @ ./indices.jl:345 [inlined]
  [6] view
    @ ./subarray.jl:183 [inlined]
  [7] parameter_values(p::ModelingToolkit.MTKParameters{…}, pind::ModelingToolkit.ParameterIndex{…})
    @ ModelingToolkit ~/.julia/packages/ModelingToolkit/yHDgG/src/systems/parameter_buffer.jl:367
  [8] parameter_values(prob::ODEProblem{…}, i::ModelingToolkit.ParameterIndex{…})
    @ SymbolicIndexingInterface ~/.julia/packages/SymbolicIndexingInterface/UG89Q/src/value_provider_interface.jl:23
  [9] macro expansion
    @ ~/.julia/packages/SymbolicIndexingInterface/UG89Q/src/batched_interface.jl:134 [inlined]
 [10] macro expansion
    @ ~/.julia/packages/RuntimeGeneratedFunctions/M9ZX8/src/RuntimeGeneratedFunctions.jl:163 [inlined]
 [11] macro expansion
    @ ./none:0 [inlined]
 [12] generated_callfunc
    @ ./none:0 [inlined]
 [13] (::RuntimeGeneratedFunctions.RuntimeGeneratedFunction{…})(::ODEProblem{…}, ::ODEProblem{…})
    @ RuntimeGeneratedFunctions ~/.julia/packages/RuntimeGeneratedFunctions/M9ZX8/src/RuntimeGeneratedFunctions.jl:150
 [14] (::SymbolicIndexingInterface.var"#_getter#70"{…})(::ODEProblem{…}, ::ODEProblem{…})
    @ SymbolicIndexingInterface ~/.julia/packages/SymbolicIndexingInterface/UG89Q/src/batched_interface.jl:175
 [15] top-level scope
    @ Untitled-1:36
Some type information was truncated. Use `show(err)` to see complete types.

[AayushSabharwal]

The error above is fixed by this PR