[submodule][202503] Update submodule sonic-platform-daemons to the latest HEAD automatically (#1601)

#### Why I did it
src/sonic-platform-daemons
```
* ec79b8d - (HEAD -> 202503, origin/202503) Merge pull request #49 from mssonicbld/sonicbld/202503-merge (23 hours ago) [mssonicbld]
* 9ab51fe - Merge branch '202412' of https://github.com/Azure/sonic-platform-daemons.msft into 202503 (23 hours ago) [Sonic Automation]
* c5b86da - (origin/202412) Check low power mode before vdm handling (#48) (2 days ago) [mssonicbld]
```
#### How I did it
#### How to verify it
#### Description for the changelog

Author: mssonicbld