Optimize code to replace the df

[Kaniyaki]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 82.35294% with 6 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/estimagic/parameters/check_constraints.py	73.91%	6 Missing ⚠️

Files with missing lines	Coverage Δ
tests/parameters/test_check_constraints.py	100.00% <100.00%> (ø)
src/estimagic/parameters/check_constraints.py	87.39% <73.91%> (-0.57%)	⬇️

[Kaniyaki]

Optimized the "check_fixes_and_bounds" function, which originally had a runtime of 5.61 ms.
The main problem was that it used DataFrame.
Instead of it, I used a dictionary and added the "_iloc" function as a substitute for DataFrame.iloc. Current runtime is 55 µs, which is a significant improvement.
In the end, I made sure that all tests passed, and they did.
Below, you can see the comparison for the runtime using %timeit and %lprun.
lprun_comparison.pdf
timeit_comparison.pdf

[janosg]

Again, sorry for the delay. Great work, just polished it a bit.