[BugFix] Fix missing comunicated PDFs for FreeSlip

When the LBM communication is used special slices for the sides and the corners are created. These contain not enough information for the FreeSlip BCs.

lbmpy/advanced_streaming/communication.py

 import itertools
 from pystencils import Field, Assignment
 from pystencils.slicing import shift_slice, get_slice_before_ghost_layer, normalize_slice
-from lbmpy.advanced_streaming.utility import is_inplace, get_accessor, numeric_index, \
-    numeric_offsets, Timestep, get_timesteps
+from lbmpy.advanced_streaming.utility import is_inplace, get_accessor, numeric_index, Timestep, get_timesteps
 from pystencils.datahandling import SerialDataHandling
 from pystencils.enums import Target
 from itertools import chain
@@ -60,7 +59,7 @@ def get_communication_slices(
     Return the source and destination slices for periodicity handling or communication between blocks.
 
     :param stencil: The stencil used by the LB method.
-    :param comm_stencil: The stencil defining the communication directions. If None, it will be set to the 
+    :param comm_stencil: The stencil defining the communication directions. If None, it will be set to the
                          full stencil (D2Q9 in 2D, D3Q27 in 3D, etc.).
     :param streaming_pattern: The streaming pattern.
     :param prev_timestep: Timestep after which communication is run.
@@ -83,13 +82,10 @@ def get_communication_slices(
 
         for streaming_dir in set(_extend_dir(comm_dir)) & set(stencil):
             d = stencil.index(streaming_dir)
-            write_offsets = numeric_offsets(write_accesses[d])
             write_index = numeric_index(write_accesses[d])[0]
 
-            tangential_dir = tuple(s - c for s, c in zip(streaming_dir, comm_dir))
             origin_slice = get_slice_before_ghost_layer(comm_dir, ghost_layers=ghost_layers, thickness=1)
-            origin_slice = _fix_length_one_slices(origin_slice)
-            src_slice = shift_slice(_trim_slice_in_direction(origin_slice, tangential_dir), write_offsets)
+            src_slice = _fix_length_one_slices(origin_slice)
 
             neighbour_transform = _get_neighbour_transform(comm_dir, ghost_layers)
             dst_slice = shift_slice(src_slice, neighbour_transform)
@@ -114,6 +110,7 @@ def periodic_pdf_copy_kernel(pdf_field, src_slice, dst_slice,
     src_slice = src_slice[:-1]
     dst_slice = dst_slice[:-1]
 
+    # TODO this is the domain_size with GL
     if domain_size is None:
         domain_size = pdf_field.spatial_shape