[202505] FEC histogram with ability to clear stat (#4075)

[mihirpat1]

202505 cherry-pick PR for #4075
202505 specific changes

• Modified the sequence number gaps in counter_bucket_dict since the packet trimming related changes (SAI_PORT_STAT_TX_TRIM_PACKETS and SAI_PORT_STAT_DROPPED_TRIM_PACKETS) from master branch were not present on 202505
• Changed the value of BUCKET_NUM from 50 to 66 since added 16 entries
• Added fec_hist_only parameter in cnstat_print function
• Modified definition of cnstat_print to display accumulated FEC BIN counters

What I did

Added new CLI "portstat -fh" for displaying the FEC histogram which accounts for clear counter by "portstat -c"

How I did it

Added new CLI

 root@sonic:~# portstat -fh 
 Last cached time was 2025-10-02T16:43:57.934081
       IFACE           BIN0        BIN1       BIN2    BIN3    BIN4    BIN5    BIN6    BIN7    BIN8    BIN9    BIN10    BIN11    BIN12    BIN13    BIN14    BIN15
 -----------  -------------  ----------  ---------  ------  ------  ------  ------  ------  ------  ------  -------  -------  -------  -------  -------  -------
   Ethernet0  4,374,661,575         340          1       0       0       0       0       0       0       0        0        0        0        0        0        0
   Ethernet8  4,374,590,263       8,069          9       0       0       0       0       0       0       0        0        0        0        0        0        0
  Ethernet16  4,374,660,911       3,187          4       0       0       0       0       0       0       0        0        0        0        0        0        0
  Ethernet24  4,374,594,305      57,484        502       0       0       0       0       0       0       0        0        0        0        0        0        0
  Ethernet32  4,374,649,615         116          0       0       0       0       0       0       0       0        0        0        0        0        0        0
  Ethernet40 

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).