Fix schema error when running ecephys write_nwb with LIMS

LIMS calls the write_nwb module and specifies ecephys channel
structure id and acronym as `manual_structure_id` and
`manual_structure_acronym` in the input json.

It appears #1075 modified the ecephys write_nwb schema
from the expected values.

This commit changes back the ecephys write_nwb schema to expect:
`manual_structure_id` and `manual_structure_acronym`.

allensdk/brain_observatory/ecephys/write_nwb/_schemas.py

@@ -26,8 +26,8 @@ class Channel(RaisingSchema):
     local_index = Int(required=True)
     probe_vertical_position = Int(required=True)
     probe_horizontal_position = Int(required=True)
-    structure_id = Int(required=True, allow_none=True)
-    structure_acronym = String(required=True, allow_none=True)
+    manual_structure_id = Int(required=True, allow_none=True)
+    manual_structure_acronym = String(required=True, allow_none=True)
 
 
 class Unit(RaisingSchema):