fix(api): truncate plate reader floating point results to third decim…

…al place (#16919)

Covers EXEC-1019
Ensure the plate reader values are truncated to the third decimal place after being read during a protocol.

api/src/opentrons/protocol_engine/state/modules.py

@@ -1268,7 +1268,10 @@ def convert_absorbance_reader_data_points(
                 row = chr(ord("A") + i // 12)  # Convert index to row (A-H)
                 col = (i % 12) + 1  # Convert index to column (1-12)
                 well_key = f"{row}{col}"
-                well_map[well_key] = value
+                truncated_value = float(
+                    "{:.5}".format(str(value))
+                )  # Truncate the returned value to the third decimal place
+                well_map[well_key] = truncated_value
             return well_map
         else:
             raise ValueError(