fix errors from abcd conversion practice

[yibeichan]

1. fixed csv encoding
   -> add different csv encoding types
2. Error: Error during conversion: Validation type: abcd_id is not supported yet. Please add it to VALUE_TYPE_MAP.
   -> if validation_type is not in VALUE_TYPE_MAP, we set it as xsd:string but add it to additionalNotesObj
3. Warning/Error: Value 24.0 is not a valid xsd:integer
   -> accept both integer and decimal values for min/max validation
4. Warning/Error: Unexpected input type for choices in zyg_description: input type static (original in redcap: descriptive), values: 1, Twin1 (t1) 2, Twin2 (t2)
   -> REDCap allows descriptive fields (static text) to have choices, which seems contradictory since descriptive fields aren't supposed to collect responses. This is likely being used for display purposes where the choices provide additional information or structure rather than actual selection options.
   -> Treats choices in descriptive fields as valid data rather than errors
   -> Stores them in a separate additionalChoiceInfo property to preserve the information