AmiciObjective / RelativeAmiciCalculator doesn't always provide `inner_parameters`

[dweindl]

Using hierarchical optimization based on RelativeAmiciCalculator, the return value of AmiciObjective.__call__(..., return_dict=True) sometimes contains inner_parameters, sometimes it doesn't. I didn't see a clear pattern yet. I would have expected inner_parameters to always be present.

• sensi_orders=(0,), failed simulation -> inner_parameters consistently absent -> okay, I'd say
• sensi_orders=(0,), successful simulation -> inner_parameters sometimes present -> not okay
• sensi_orders=(0, 1), successful simulation -> inner_parameters consistently absent -> not okay
• sensi_orders=(0, 1), failed simulation -> inner_parameters consistently absent -> okay, I'd say

[PaulJonasJost]

@dweindl, @Doresic, seems closed by #1333, please reopen if I understood this wrong.