Fixed TaskDoc for vasp_ml MD calculations.

[davidwaroquiers]

This PR solves a problem for calculations with Vasp ML. Indeed, the number of ionic_steps from the vasprun is not taking into account the steps performed with the ML model.

Contributor Checklist

• [ ] I have run the tests locally and they passed.
• [ ] I have added tests, or extended existing tests, to cover any new features or bugs fixed in this PR

[codecov-commenter]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (d0276a1) 90.15% compared to head (e23613f) 88.90%. Report is 2 commits behind head on main.

Files	Patch %	Lines
emmet-core/emmet/core/vasp/calculation.py	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #939 +/- ## ========================================== - Coverage 90.15% 88.90% -1.26% ========================================== Files 138 109 -29 Lines 13159 10086 -3073 ========================================== - Hits 11864 8967 -2897 + Misses 1295 1119 -176 ```

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