Improve performance of 1D visualization for curved `P4estMesh`

[ranocha]

I improved the algorithm to find 1D points used for visualization in linear P4estMeshes in #2334 and #2340. It would be nice to extend this to curved meshes as well, see the comments in

Trixi.jl/src/visualization/utilities_p4est_t8code.jl

Lines 19 to 34 in 0ad97bc

	function unstructured_2d_to_1d_curve(u, mesh::P4estMesh{2, 2, Float64},
	equations, dg::DGSEM, cache,
	curve, slice,
	point, nvisnodes,
	solution_variables)
	# TODO: Currently, the efficient search functionality is only implemented
	# for linear meshes. If the mesh is not linear, we fall back to the naive
	# but general approach.
	if length(mesh.nodes) != 2
	return unstructured_2d_to_1d_curve_general(u, mesh, equations,
	dg, cache,
	curve, slice,
	point, nvisnodes,
	solution_variables)
	end
	# From here on, we know that we only have to deal with a linear mesh.

and

Trixi.jl/src/visualization/utilities_p4est_t8code.jl

Lines 312 to 324 in 0ad97bc

	function unstructured_3d_to_1d_curve(u,
	mesh::Union{P4estMesh{3, 3, Float64},
	T8codeMesh{3, Float64}},
	equations, dg::DGSEM, cache,
	curve, solution_variables)
	# TODO: Currently, the efficient search functionality is only implemented
	# for linear meshes. If the mesh is not linear, we fall back to the naive
	# but general approach.
	if length(mesh.nodes) != 2
	return unstructured_3d_to_1d_curve_general(u, equations, dg, cache,
	curve, solution_variables)
	end
	# From here on, we know that we only have to deal with a linear mesh.