fix: fix `setindex!` not erroring appropriately for integrators

[AayushSabharwal]

Close #653

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.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 30.12%. Comparing base (7888fa4) to head (a07a002).

Files	Patch %	Lines
src/integrator_interface.jl	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #657 +/- ## ========================================== + Coverage 30.03% 30.12% +0.09% ========================================== Files 55 55 Lines 4309 4308 -1 ========================================== + Hits 1294 1298 +4 + Misses 3015 3010 -5 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.