Add missing methods to lists/list_column_view.pxd in pylibcudf (#16175)

Apart of #15162

Authors:
  - Matthew Murray (https://github.com/Matt711)

Approvers:
  - GALI PREM SAGAR (https://github.com/galipremsagar)

URL: #16175

python/cudf/cudf/_lib/pylibcudf/libcudf/lists/lists_column_view.pxd

@@ -10,7 +10,9 @@ from cudf._lib.pylibcudf.libcudf.types cimport size_type
 cdef extern from "cudf/lists/lists_column_view.hpp" namespace "cudf" nogil:
     cdef cppclass lists_column_view(column_view):
         lists_column_view() except +
+        lists_column_view(const lists_column_view& lists_column) except +
         lists_column_view(const column_view& lists_column) except +
+        lists_column_view& operator=(const lists_column_view&) except +
         column_view parent() except +
         column_view offsets() except +
         column_view child() except +