refactor: improve DateTime handling in GraphQL builder

- Streamlined DateTime serialization and parsing logic in the GraphQL builder for enhanced clarity and maintainability.
- Removed commented-out code to reduce clutter and improve code readability.
- Ensured consistent error handling for invalid DateTime values.

src/Graphql/graphql.builder.ts

@@ -130,28 +130,24 @@ export class Builder extends SchemaBuilder<SchemaBuilderOption> {
     this.generator = new PrismaCrudGenerator<BuilderTypes>(this)
     this.scalarType('DateTime', {
       serialize: (value) => {
-        // Serialize outgoing DateTime to ISO string
         if (typeof value === 'string') {
           return value
         }
         if (typeof value === 'object' && value !== null && 'toISO' in value) {
           return value
         }
-        // if value = Date, convert to DateTime
         if (value instanceof Date) {
           return DateTimeUtils.toIsoString(DateTimeUtils.fromDate(value))
         }
         throw new Error('Invalid DateTime')
       },
       parseValue: (value) => {
-        // Parse incoming ISO string to Luxon DateTime
         if (typeof value === 'string') {
           return DateTimeUtils.fromIsoString(value)
         }
         throw new Error('Invalid DateTime')
       },
       parseLiteral: (ast) => {
-        // parse string to DateTime
         if (ast.kind === Kind.STRING) {
           return DateTimeUtils.fromIsoString(ast.value)
         }