[AWS Firehose quickstart] Port 4433 to serverless docs

[alaudazzi]

Description

Port #4433 to serverless docs.

Documentation sets edited in this PR

Check all that apply.

• Stateful (docs/en/observability/*)
• Serverless (docs/en/serverless/*)
• Integrations Developer Guide (docs/en/integrations/*)
• None of the above

Related issue

Closes #4434

Checklist

• Product/Engineering Review
• Writer Review

Follow-up tasks

Select one.

• This PR does not need to be ported to another doc set because:
  • The concepts in this PR only apply to one doc set (serverless or stateful)
  • The PR contains edits to both doc sets (serverless and stateful)
• This PR needs to be ported to another doc set:
  • Port to stateful docs: <link to PR or tracking issue>
  • Port to serverless docs: <link to PR or tracking issue>

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[mdbirnstiehl]

LGTM!

[eedugon]

LGTM! I've added a comment about the pre-requisites section, just in case it's useful.

[alaudazzi]

@mykolaharmash
Can you have a look and confirm the text is OK for serverless?

[mykolaharmash]

Looks great, thank you ✨

[eedugon]

LGTM!