[submodule] [202012] Update sonic-telemetry HEAD

[zbud-msft]

Why I did it

56aa539 Sachin Holla Tue Jun 20 03:46:08 2023 +0530 Fix sonic-mgmt-common version in pipeline build (#124)
4264949 Zain Budhwani Fri Jun 9 16:12:06 2023 -0700 Change log level (#118)

Work item tracking

• Microsoft ADO (number only): 23021533

How I did it

Update ptr

How to verify it

Pipeline

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111
• 202205
• 202211
• 202305

Tested branch (Please provide the tested image version)

Description for the changelog

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[qiluo-msft]

I see similar PR already merged.

$ git show 6884c2e9f
commit 6884c2e9f9583b97bac7fc2773416f5b0f1a2a3c
Author: mssonicbld <79238446+mssonicbld@users.noreply.github.com>
Date:   Thu Jul 6 15:08:01 2023 +0800

    [submodule] Update submodule sonic-telemetry to the latest HEAD automatically (#15543)

    #### Why I did it
    src/sonic-telemetry
    ```
    * 56aa539 - (HEAD -> 202012, origin/202012) Fix sonic-mgmt-common version in pipeline build (#124) (2 weeks ago) [Sachin Holla]
    * 4264949 - Change log level (#118) (4 weeks ago) [Zain Budhwani]
    ```