GH-1454: Declare ID as nullable in the local files Substrait test plan

local_files_users.json declared ID as required, but the Parquet file
the test reads has an optional id column and the test expects a
nullable ID. Arrow C++ main now keeps the input nullability of
projected fields (apache/arrow#51691), so the scan returned ID as not
null and testRunQueryLocalFiles failed in the nightly build.

Author: jbonofre

dataset/src/test/resources/substrait/local_files_users.json

@@ -22,7 +22,7 @@
                   "types": [{
                     "i32": {
                       "typeVariationReference": 0,
-                      "nullability": "NULLABILITY_REQUIRED"
+                      "nullability": "NULLABILITY_NULLABLE"
                     }
                   }, {
                     "varchar": {