Tear down Tetragon PoC

[samsimpson1]

User Need

As an infrastructure maintainer
I want to tear down the Tetragon proof-of-concept in integration
so that I can be confident we're not wasting resources and leaving unnecessary software running in our environment

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Context

(Add any extra context, links, diagrams, stakeholder interviews, etc.)

We decided in #3708 to not continue with Tetragon, so we need to remove it from our integration cluster.

This was created in #3645

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What’s Needed

List anything the solution must do or be (behaviour, performance, security, UX, etc.).

• Uninstall Tetragon from the integration cluster
• Remove the S3 bucket Tetragon uses to store events
• Remove Tetragon Terraform and Helm charts files

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Acceptance Criteria

Clear, measurable conditions to verify the story is complete and valuable.

• Tetragon is no longer installed in integration
• No Tetragon cloud infrastructure still exists in the integration AWS account
• IaC for Tetragon has been removed