fixed linting issues

pkg/plugin/implementation/publisher/publisher_test.go

@@ -235,12 +235,6 @@ func (m *mockChannel) Close() error {
 	return nil
 }
 
-type mockConnection struct{}
-
-func (m *mockConnection) Close() error {
-	return nil
-}
-
 func TestNewPublisherSucess(t *testing.T) {
 	originalDialFunc := DialFunc
 	originalChannelFunc := ChannelFunc
@@ -284,18 +278,6 @@ func TestNewPublisherSucess(t *testing.T) {
 	}
 }
 
-type mockChannelFailDeclare struct{}
-
-func (m *mockChannelFailDeclare) PublishWithContext(ctx context.Context, exchange, key string, mandatory, immediate bool, msg amqp091.Publishing) error {
-	return nil
-}
-func (m *mockChannelFailDeclare) ExchangeDeclare(name, kind string, durable, autoDelete, internal, noWait bool, args amqp091.Table) error {
-	return fmt.Errorf("simulated exchange declare error")
-}
-func (m *mockChannelFailDeclare) Close() error {
-	return nil
-}
-
 func TestNewPublisherFailures(t *testing.T) {
 	tests := []struct {
 		name          string