fix: handle non-mtkcompile systems in full_equations initialization

[AayushSabharwal]

The test and comments describe the error. This arises from a failure in Catalyst.

[github-actions]

Benchmark Results (Julia vlts)

Time benchmarks

	master	07b73ac...	master / 07b73ac...
ODEProblem	7.16 ± 1 ms	10.6 ± 2.1 ms	0.678 ± 0.16
init	0.0935 ± 0.032 ms	0.108 ± 0.023 ms	0.865 ± 0.35
large_parameter_init/ODEProblem	0.0355 ± 0.0063 s	0.0378 ± 0.0083 s	0.938 ± 0.26
large_parameter_init/init	0.107 ± 0.035 ms	0.107 ± 0.032 ms	0.995 ± 0.44
mtkcompile	11.1 ± 2 ms	17.7 ± 3.3 ms	0.629 ± 0.16
sparse_analytical_jacobian/ODEProblem	31.3 ± 4 ms	0.0431 ± 0.0053 s	0.725 ± 0.13
sparse_analytical_jacobian/f_iip	0.07 ± 0 μs	0.08 ± 0.01 μs	0.875 ± 0.11
sparse_analytical_jacobian/f_oop	0.374 ± 0.0086 ms	0.385 ± 0.016 ms	0.97 ± 0.045
time_to_load	6.33 ± 1.7 s	7.66 ± 0.28 s	0.827 ± 0.23

Memory benchmarks

	master	07b73ac...	master / 07b73ac...
ODEProblem	31.5 k allocs: 1.95 MB	0.0321 M allocs: 1.98 MB	0.985
init	0.416 k allocs: 0.0697 MB	0.416 k allocs: 0.0697 MB	1
large_parameter_init/ODEProblem	0.316 M allocs: 11.5 MB	0.316 M allocs: 11.5 MB	1
large_parameter_init/init	0.604 k allocs: 0.172 MB	0.604 k allocs: 0.172 MB	1
mtkcompile	0.0596 M allocs: 3.45 MB	0.0596 M allocs: 3.45 MB	1
sparse_analytical_jacobian/ODEProblem	0.196 M allocs: 8.31 MB	0.196 M allocs: 8.31 MB	1
sparse_analytical_jacobian/f_iip	0 allocs: 0 B	0 allocs: 0 B
sparse_analytical_jacobian/f_oop	0.634 k allocs: 19.6 kB	0.634 k allocs: 19.6 kB	1
time_to_load	0.153 k allocs: 14.6 kB	0.153 k allocs: 14.6 kB	1

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	master	07b73ac...	master / 07b73ac...
ODEProblem	5.66 ± 0.59 ms	5.66 ± 0.67 ms	0.999 ± 0.16
init	0.0496 ± 0.0077 ms	0.0522 ± 0.0081 ms	0.95 ± 0.21
large_parameter_init/ODEProblem	25.4 ± 5 ms	28 ± 5.3 ms	0.905 ± 0.25
large_parameter_init/init	0.0541 ± 0.025 ms	0.0722 ± 0.035 ms	0.748 ± 0.5
mtkcompile	7.51 ± 0.56 ms	7.35 ± 0.57 ms	1.02 ± 0.11
sparse_analytical_jacobian/ODEProblem	20.7 ± 2.8 ms	26.1 ± 2.2 ms	0.796 ± 0.13
sparse_analytical_jacobian/f_iip	0.06 ± 0.01 μs	0.07 ± 0.01 μs	0.857 ± 0.19
sparse_analytical_jacobian/f_oop	0.108 ± 0.013 ms	0.114 ± 0.054 ms	0.949 ± 0.47
time_to_load	4.78 ± 0.084 s	4.84 ± 0.15 s	0.987 ± 0.036

Memory benchmarks

	master	07b73ac...	master / 07b73ac...
ODEProblem	30.1 k allocs: 1.75 MB	30.1 k allocs: 1.76 MB	0.999
init	0.415 k allocs: 0.0517 MB	0.415 k allocs: 0.0517 MB	1
large_parameter_init/ODEProblem	0.329 M allocs: 12.5 MB	0.329 M allocs: 12.5 MB	1
large_parameter_init/init	0.798 k allocs: 0.151 MB	0.798 k allocs: 0.151 MB	1
mtkcompile	0.0561 M allocs: 2.75 MB	0.0561 M allocs: 2.75 MB	1
sparse_analytical_jacobian/ODEProblem	0.189 M allocs: 7.28 MB	0.189 M allocs: 7.28 MB	1
sparse_analytical_jacobian/f_iip	0 allocs: 0 B	0 allocs: 0 B
sparse_analytical_jacobian/f_oop	0.848 k allocs: 27 kB	0.848 k allocs: 27 kB	1
time_to_load	0.146 k allocs: 11.4 kB	0.146 k allocs: 11.4 kB	1