Add ChecksumError handling to FatError conversion

Software/MainBoard/rust/src/fat_error.rs

@@ -319,6 +319,9 @@ impl From<BmsProtocolError> for FatError {
             BmsProtocolError::I2cCommunicationError =>FatError::String {
                 error: "I2C communication error".to_string(),
             },
+            BmsProtocolError::ChecksumError => FatError::String {
+                error: "BMS checksum error".to_string(),
+            },
         }
     }
 }