update(read_binary_data_from_file): update for binary layer files wit…

…h multiple layers

Previously code read the entire file without stripping headers after first layer. Enforce read_multi_layer=True if data_size != ncpl

flopy/mf6/data/mffileaccess.py

@@ -399,6 +399,9 @@ def read_binary_data_from_file(
     ):
         import flopy.utils.binaryfile as bf
 
+        if data_size != modelgrid.ncpl:
+            read_multi_layer = True
+
         fd = self._open_ext_file(fname, True)
         numpy_type, name = self.datum_to_numpy_type(data_type)
         header_dtype = bf.BinaryHeader.set_dtype(