test: update expectations

Signed-off-by: Andres Taylor <andres@planetscale.com>

go/vt/vtexplain/testdata/multi-output/selectsharded-output.txt

@@ -128,7 +128,7 @@ select name from user where id not in (select id from t1) /* non-correlated subq
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 select name from user where exists (select id from t1) /* non-correlated subquery as EXISTS */
 
-1 ks_unsharded/-: select 1 from t1 limit 10001 /* non-correlated subquery as EXISTS */
+1 ks_unsharded/-: select 1 from t1 limit 1 /* non-correlated subquery as EXISTS */
 2 ks_sharded/-40: select `name` from `user` where 1 limit 10001 /* non-correlated subquery as EXISTS */
 2 ks_sharded/40-80: select `name` from `user` where 1 limit 10001 /* non-correlated subquery as EXISTS */
 2 ks_sharded/80-c0: select `name` from `user` where 1 limit 10001 /* non-correlated subquery as EXISTS */