Relative: Fix return of inner parameters on objective call

[Doresic]

There was a bad implementation of inner parameter returning on call of objective. Previously, the InnerCalculatorCollector would take note of self.best_fval such that it returns inner_parameters only in cases a better objective function value was found. This was ok during optimization, but then if one wanted to get inner parameters for some other outer parameter vector for which the objective function would not be better, the inner parameters would not be returned.

This is bad practice: to save current states in the calculator and objective objects. So now, after an optimization start is finished, the hierarchical_decorator instead calls the objective once more with the best outer parameters found to obtain the inner parameters for that outer vector.

There some small update in the visualize of model_fit.time_trajectory_model. Was not working with the current implementation due to recent hierarchical structure changes.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 85.71429% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 84.26%. Comparing base (9cf4bf2) to head (476c2b6).

Files	Patch %	Lines
pypesto/visualize/model_fit.py	50.00%	2 Missing :warning:

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #1333 +/- ## ======================================== Coverage 84.25% 84.26% ======================================== Files 152 152 Lines 12452 12441 -11 ======================================== - Hits 10492 10483 -9 + Misses 1960 1958 -2 ```

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