[notebook]: pin the source code in experimental notebook

[zxkane]

Describe the bug
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The experimental notebook is fetching the latest code from main branch, the environment might not work any more if the main branch introduces the breaking change.

To Reproduce
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Expected behavior
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Please complete the following information about the solution:

• Version: [e.g. v1.0.0]

To get the version of the solution, you can look at the description of the created CloudFormation stack. For example, "(SO0021) - Video On Demand workflow with AWS Step Functions, MediaConvert, MediaPackage, S3, CloudFront and DynamoDB. Version v5.0.0". If the description does not contain the version information, you can look at the mappings section of the template:

Mappings:
  SourceCode:
    General:
      S3Bucket: "solutions"
      KeyPrefix: "video-on-demand-on-aws/v5.0.0"

• Region: [e.g. us-east-1]
• Was the solution modified from the version published on this repository?
• If the answer to the previous question was yes, are the changes available on GitHub?
• Have you checked your service quotas for the sevices this solution uses?
• Were there any errors in the CloudWatch Logs?

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Additional context
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