fix: use joi positive and integer validators on HD_MAX_DOCUMENT_LENGTH

validate HD_MAX_DOCUMENT_LENGTH with the positive and integer validators of Joi.

See also:
- https://joi.dev/api/#numberpositive
- https://joi.dev/api/#numberinteger

Signed-off-by: Philip Molares <philip.molares@udo.edu>

src/config/note.config.ts

@@ -21,6 +21,8 @@ const schema = Joi.object({
     .label('HD_FORBIDDEN_NOTE_IDS'),
   maxDocumentLength: Joi.number()
     .default(100000)
+    .positive()
+    .integer()
     .optional()
     .label('HD_MAX_DOCUMENT_LENGTH'),
 });