GetSimulcastConfig had to be overloaded in order to not break downstream client tests when the API was changed. Now that the downstream client has been updated to use the new API, we can remove the overloaded function. Bug: webrtc:8630 Change-Id: I5d5d494e0579e60858d6efbb4715761394874b38 Reviewed-on: https://webrtc-review.googlesource.com/38882 Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org> Commit-Queue: Seth Hampson <shampson@webrtc.org> Cr-Commit-Position: refs/heads/master@{#21590}