[DPB] XCVRD not able to fetch the new port SFP info after perform dynamic port breakdown

[keboliu]

Description

XCVRD is based on the assumption that all the ports will be created during the SONiC boot-up stage, with no port add/remove in the fly.
Dynamic port breakdown breaks this assumption, now XCVRD needs to subscribe to the port add/remove to make the ports --> SFP mapping always updated.

Steps to reproduce the issue:

1. perform port breakdown with command "config interface breakout Ethernet8 2x200G[100G,50G,40G,25G,10G,1G] -v -y"
2. In the output of "show interface status" will see that the "Type" of the new port Ethernet12 is 'N/A'

Describe the results you received:

new "Type" available in the "show interface status" output for the new breakdown port.

Describe the results you expected:

the "Type" of the interface should be avalaible.

Additional information you deem important (e.g. issue happens only occasionally):

**Output of `show version`:**

```
(paste your output here)
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**Attach debug file `sudo generate_dump`:**

```
(paste your output here)
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[anshuv-mfst]

Issue related to Dynamic port breakout. This is not supported as of today.

[anshuv-mfst]

@zhenggen-xu @jleveque - could you please take a look.

[zhenggen-xu]

The issue follows to new requirement category, where we need community to support the effort.

[liat-grozovik]

@keboliu please suggest the fix and we will discuss it on the workgroup.

[keboliu]

PR to fix this issue:
sonic-net/SONiC#839
sonic-net/sonic-platform-daemons#212

[keboliu]

issue fixed by PRs mentioned in the above comments.