Describe the bug
After calling XACK on a stream the message still shows up in the pending list.

Tested on keydb v5.3.3 and v6.0.16 with active replica.

edit: see updated test procedure in comment #238 (comment)

** Log Files **

127.0.0.1:6379> XPENDING reached_limits prov_reached_limits - + 10

1. 1. "1601371253314-0"
   2. "provreachedlimitsTask"
   3. (integer) 14288902
   4. (integer) 1
2. 1. "1601376154730-0"
   2. "provreachedlimitsTask"
   3. (integer) 9387420
   4. (integer) 1

127.0.0.1:6379> XACK reached_limits prov_reached_limits 1601371253314-0
(integer) 1

127.0.0.1:6379> XPENDING reached_limits prov_reached_limits - + 10

1. 1. "1601371253314-0"
   2. "provreachedlimitsTask"
   3. (integer) 15472971
   4. (integer) 1
2. 1. "1601376154730-0"
   2. "provreachedlimitsTask"
   3. (integer) 10571489
   4. (integer) 1