trap_rates.lua get value error (sonic-net#3219)

why I did:
    If the SAI_COUNTER_STAT_PACKETS field in the COUNTERS table in the counter db is 0,
    it will be calculated as a Boolean value by trap_rates.lua, resulting in a script operation error.

what I did:
    Force in_pkts to be converted into a numerical value before operation

orchagent/trap_rates.lua

@@ -36,7 +36,8 @@ for i = 1, n do
     logit(initialized)
 
     -- Get new COUNTERS values
-    local in_pkts = redis.call('HGET', counters_table_name .. ':' .. KEYS[i], 'SAI_COUNTER_STAT_PACKETS')
+    local in_pkts_str = redis.call('HGET', counters_table_name .. ':' .. KEYS[i], 'SAI_COUNTER_STAT_PACKETS')
+    local in_pkts = tonumber(in_pkts_str) or 0
 
     if initialized == 'DONE' or initialized == 'COUNTERS_LAST' then
         -- Get old COUNTERS values