chore: Update CODEOWNERS to streamline team assignments (#2930)

Removed Librarian ownership entries for sidekick and added ownership for
surfer. This should allow for the correct teams to get assigned PRs.

We have updated the Librarian repository settings so anyone in cloud SDK
org can approve a PR even if they aren't a code owner.

---------

Signed-off-by: ldetmer <[email protected]>

Author: ldetmer

.github/CODEOWNERS

@@ -5,5 +5,10 @@
 # The owners for all files in the repo.
 * @googleapis/cloud-sdk-librarian-team
 
-/cmd/sidekick/ @googleapis/cloud-sdk-sidekick-team @googleapis/cloud-sdk-librarian-team
-/internal/sidekick/ @googleapis/cloud-sdk-sidekick-team @googleapis/cloud-sdk-librarian-team
+# Locations for all sidekick code.
+/cmd/sidekick/ @googleapis/cloud-sdk-sidekick-team
+/internal/sidekick/ @googleapis/cloud-sdk-sidekick-team
+
+# Locations for all surfer code.
+/cmd/surfer/ @googleapis/cloud-sdk-surfer-team
+/internal/surfer/ @googleapis/cloud-sdk-surfer-team