chore: remove unused proto imports (#579)

* chore: remove unused proto imports

PiperOrigin-RevId: 468735472

Source-Link: googleapis/googleapis@cfa1b37

Source-Link: googleapis/googleapis-gen@09b7666
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packages/google-cloud-iot/protos/google/cloud/iot/v1/device_manager.proto

@@ -25,7 +25,6 @@ import "google/iam/v1/iam_policy.proto";
 import "google/iam/v1/policy.proto";
 import "google/protobuf/empty.proto";
 import "google/protobuf/field_mask.proto";
-import "google/rpc/status.proto";
 
 option cc_enable_arenas = true;
 option go_package = "google.golang.org/genproto/googleapis/cloud/iot/v1;iot";