fix the call arguments

https://pysam.readthedocs.io/en/v0.21.0/api.html?highlight=AlignedSegment#pysam.AlignedSegment.tostring

lib/galaxy/datatypes/binary.py

@@ -664,7 +664,7 @@ def get_chunk(self, trans, dataset: HasFileName, offset: int = 0, ck_size: Optio
                             break
 
                         offset = bamfile.tell()
-                        bamline = alignment.to_string(bamfile)
+                        bamline = alignment.to_string()
                         # With multiple tags, Galaxy would display each as a separate column
                         # because the 'to_string()' function uses tabs also between tags.
                         # Below code will turn these extra tabs into spaces.