Add missing test dependencies to downstream Project.toml

Add packages that are used by downstream tests but were not listed:
- SymbolicIndexingInterface (used in symbol_indexing.jl)
- Zygote (used in symbol_indexing.jl)
- Tables (used via testutils.jl)
- ArrayInterface (used in odesolve.jl)
- NLsolve (used in odesolve.jl)

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: claude

test/downstream/Project.toml

@@ -1,15 +1,26 @@
 [deps]
+ArrayInterface = "4fba245c-0d91-5ea0-9b3e-6abc04ee57a9"
 ModelingToolkit = "961ee093-0014-501f-94e3-6117800e7a78"
 MonteCarloMeasurements = "0987c9cc-fe09-11e8-30f0-b96dd679fdca"
+NLsolve = "2774e3e8-f4cf-5e23-947b-6d7e65073b56"
 OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
+RecursiveArrayTools = "731186ca-8d62-57ce-b412-fbd966d074cd"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
+SymbolicIndexingInterface = "2efcf032-c050-4f8e-a9bb-153293bab1f5"
+Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 Tracker = "9f7883ad-71c0-57eb-9f7f-b5c9e6d3789c"
 Unitful = "1986cc42-f94f-5a68-af5c-568840ba703d"
+Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
 
 [compat]
+ArrayInterface = "7"
 ModelingToolkit = "8.33, 9"
 MonteCarloMeasurements = "1.1"
+NLsolve = "4"
 OrdinaryDiffEq = "6.31"
 StaticArrays = "1"
+SymbolicIndexingInterface = "0.3"
+Tables = "1"
 Tracker = "0.2"
 Unitful = "1.17"
+Zygote = "0.6, 0.7"