add optional `continuous_modification` argument to `reeval_internals_due_to_modification!`

[oscardssmith]

When set to false allows the integrator to skip recalculating the interpolation data. This is a prereq to https://github.com/SciML/OrdinaryDiffEq.jl/pull/2141 being finished.

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: 2 lines in your changes are missing coverage. Please review.

Comparison is base (f457edc) 26.33% compared to head (3ef766a) 26.32%.

Files	Patch %	Lines
src/integrator_interface.jl	0.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #625 +/- ## ========================================== - Coverage 26.33% 26.32% -0.02% ========================================== Files 55 55 Lines 4249 4251 +2 ========================================== Hits 1119 1119 - Misses 3130 3132 +2 ```

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