chore: improve no file error, remove unused code

Author: kevinkim-ogp

packages/backend/src/apps/aisay/common/constants.ts

@@ -1,4 +1,3 @@
-export const MAX_FILE_SIZE = 6 * 1024 * 1024 // 6 MB
 export const DOCUMENT_TYPES = [
   'BANK_STATEMENT',
   'CHEQUE',

packages/backend/src/apps/aisay/common/schema.ts

@@ -8,7 +8,8 @@ export const fileSchema = z.string().transform((value, context) => {
   if (!parseS3Id(value)) {
     context.addIssue({
       code: z.ZodIssueCode.custom,
-      message: `${value} is not a S3 ID.`,
+      message: `No file was provided`,
+      fatal: true,
     })
     return z.NEVER
   }