feat(aws_cloudwatch_logs sink): allow setting the log class

[vivshaw]

Summary

as captured in #22008, it's not currently possible to set the log group used by create_missing_group. this means it always defaults to Standard, and one cannot select Infrequent Access. a prior attempt was made in #22031, but later abandoned. this PR revives that attempt. effectively the same approach is used, only minor tweaks here.

change is backwards-compatible, all existing uses should default to STANDARD just like they already do.

Vector configuration

config should look a little somethin' like this:

sources:
  demo:
    type: demo_logs
    format: json

sinks:
  cw:
    type: aws_cloudwatch_logs
    inputs: [demo]
    region: us-east-1
    group_name: "vector-ia-demo"
    stream_name: "{{ host }}"
    encoding:
      codec: json
    create_missing_group: true
    group_class: INFREQUENT_ACCESS

How did you test this PR?

cargo fmt
make check-clippy
cargo build
cargo test
make test-integration-aws
make generate-docs

lemme know if i missed anything!

Change Type

• Bug fix
• New feature
• Dependencies
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

References

• Closes: AWS CloudWatch Logs - create infrequent access type with create_missing_group #22008
• Related: feat(aws_cloudwatch_logs sink): allow setting type of log class to cr… #22031

[github-actions]

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[vivshaw]

I have read the CLA Document and I hereby sign the CLA

[vivshaw]

did this to match how y'all are handling S3 storage classes, which you have as SCREAMING_SNAKE