fix next_entity() and prev_entity() methods in command "browse"
fix next_entity() and prev_entity() methods in command "browse"

PySide6 requires the casting call Tags(entity) in entity_activated(),
which prevents finding the entity by the "is" operator.

Solutions is comparing the first DXF tag by "is" operator.

mozman/ezdxf,mozman/ezdxf,mozman/ezdxf,mozman/ezdxf,mozman/ezdxf