[Filebeat][S3] support S3 fips endpoint on govcloud regions

[ynirk]

Describe the enhancement:
AWS govcloud regions have a specific fips S3 endpoint for govcloud/fedramp compliances ref.

The only thing that change is the service name being s3-fips instead of s3 (ex: s3-fips.us-gov-east-1.amazonaws.com). We can't use the endpoint setting as it would change the endpoint for both SQS and S3.

Would it be possible to have something like a fips-enable setting?

[elasticmachine]

Pinging @elastic/siem (Team:SIEM)

[elasticmachine]

Pinging @elastic/integrations-platforms (Team:Platforms)

[kaiyan-sheng]

One followup PR for this: #21626