parametric presolve check on variable vs factor dimensionality error

[dehann]

There should be a user friendly error on parametric solve (which also suggests trying nonGaussian solve) when for example:

addVariable!(fg, :x1, )
addVariable!(fg, :x2, )

addFactor!(fg, [:x1], SomePrior)

# notice :x2 is "under constrained"
solveGraphParametric!(fg)

Above code gives weird dimension mismatch error which is hard to read or understand (but an obvious issue one understood).

Remember to point to docs also for nonGaussian: https://juliarobotics.org/Caesar.jl/latest/examples/basic_slamedonut/