Make simplifications in SymPy calculus on manifolds rely on SymPy only

[egourgoulhon]

#22801 introduced SymPy as an optional engine for symbolic calculus on manifolds. However, not all simplifications are performed by SymPy; in particular those depending on assumptions are still treated via Maxima.

Depends on #22801

CC: @man74cio @rll2021 @rwst

Component: geometry

Keywords: manifolds calculus sympy

Issue created by migration from https://trac.sagemath.org/ticket/24290

[egourgoulhon]

Dependencies: #22801

[egourgoulhon]

comment:2

Basically, one needs to pass Sage's assumptions() to SymPy and use them via refine (cf. http://docs.sympy.org/latest/modules/assumptions/refine.html) or maybe via the context manager assuming (cf. http://docs.sympy.org/latest/modules/assumptions/assume.html).