(core): add_notifications method does not send notifications as expected

[jaidisido]

Describe the bug

add_notifications method in CICDPipelineStack creates the CodeStar notification but no notification is sent when the CodePipeline pipeline fails

How to Reproduce

1. Create a DDK CICD pipeline and add notifications

CICDPipelineStack(
...
.add_notifications()

2. An SNS topic should be created. Subscribe your email address to it
3. Fail the pipeline. The user expects an email to be sent but it never arrives

Expected behavior

An email is sent when the Pipeline fails

Your project

No response

Screenshots

No response

Environment

Provide your `pip list` output, particularly the version of the AWS DDK library you used. Providing this information may significantly improve resolution times.

OS

Mac

Python version

3.7

AWS DDK version

0.2.1

Additional context

No response

[malachi-constant]

I imagine there's some issues with the SNS topic policy created, will investigate. Thanks for identifying..

[malachi-constant]

Hmm @jaidisido I'm not able to replicate

[malachi-constant]

Functionality confirmed working, unable to replicate.