FT.AGGREGATE command does not handle index fields correctly

[BagritsevichStepan]

Describe the bug
FT.AGGREGATE command does not handle index fields correctly. Some examples:

Initialize:

127.0.0.1:6379> hset key:1 word item1 foo 10 text "first key"
(integer) 3
127.0.0.1:6379> hset key:2 word item2 foo 20 text "second key"
(integer) 3
127.0.0.1:6379> ft.create index on hash schema word TAG foo NUMERIC text TEXT
OK

1. Dragonfly:

127.0.0.1:6379> ft.aggregate index "*" LOAD 2 foo text GROUPBY 2 @word @text REDUCE SUM 1 @foo AS foo_total
1) (integer) 2
2) 1) "text"
   2) "second key"
   3) "word"
   4) (nil)
   5) "foo_total"
   6) "20"
3) 1) "text"
   2) "first key"
   3) "word"
   4) (nil)
   5) "foo_total"
   6) "10"

Redis:

127.0.0.1:6379> ft.aggregate index "*" LOAD 2 foo text GROUPBY 2 @word @text REDUCE SUM 1 @foo AS foo_total
1) (integer) 2
2) 1) "word"
   2) "item2"
   3) "text"
   4) "second key"
   5) "foo_total"
   6) "20"
3) 1) "word"
   2) "item1"
   3) "text"
   4) "first key"
   5) "foo_total"
   6) "10"

2. Dragonlfy:

127.0.0.1:6379> ft.aggregate index "*" LOAD 1 @word GROUPBY 1 @word REDUCE SUM 1 @foo AS foo_total
1) (integer) 2
2) 1) "word"
   2) "item2"
   3) "foo_total"
   4) "0"
3) 1) "word"
   2) "item1"
   3) "foo_total"
   4) "0"

Redis:

1) (integer) 2
2) 1) "word"
   2) "item1"
   3) "foo_total"
   4) "10"
3) 1) "word"
   2) "item2"
   3) "foo_total"
   4) "20"