Adding Lambda S3 Event Trigger from separate CloudFormation template

bucket_template.yml

Resources:
  OriginalBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: !Sub ${Realm}-{Env}-original-bucket
      BucketEncryption: 
        ServerSideEncryptionConfiguration:
          - ServerSideEncryptionByDefault:
              SSEAlgorithm: AES256
      NotificationConfiguration:
        LambdaConfigurations:
          - Event: s3:ObjectCreated:*
            Function:
              Fn::ImportValue:
                !Sub ${Realm}-${Env}-SeparateBucketTriggerArn

lambda_template.yml

Resources:
  SeparateBucketTrigger:
    Type: 'AWS::Serverless::Function'

Outputs:
  SeparateBucketTriggerArn:
    Export:
      Name: !Sub ${Realm}-${Env}-SeparateBucketTriggerArn
    Value:
      !GetAtt SeparateBucketTrigger.Arn