[SL-TEMP] Update CODEOWNERS

[mkardous-silabs]

Testing

!!!!!!!!!! Please delete the instructions below and replace with PR
description above.

If you have an issue number, please use a syntax of Fixes #12345 and a brief
change description

If you do not have an issue number, please have a good description of the
problem and the fix. Help the reviewer understand what to expect.

Complete/append to the ### Testing section above, to describe how testing
was done. See
https://github.com/project-chip/connectedhomeip/blob/master/CONTRIBUTING.md#pull-requests

Make sure you delete these instructions (to prove you have read them).

!!!!!!!!!! Instructions end