How to install FEniCS 2019.2.0.dev0 by conda?

If you are a new user you should probably start with DOLFINx rather than DOLFIN, as DOLFIN has not been developed further Since ~2019.
See:

for some context.

Note that a more scalable and less buggy version of MeshView is available in DOLFINx (codim 0 in v0.8.0, codim 1 on main and will be in v0.9.0).