[7.17](backport #47682) Set ulimit for aerospike container so it runs

[mergify]

Proposed commit message

The aerospike container used for testing was failing with:

  CRITICAL (config): (cfg.c:4387) 1024 system file descriptors not
  enough, config specified 15000

This commit fixes it by setting the ulimit to 20000

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works. Where relevant, I have used the stresstest.sh script to run them under stress conditions and race detector to verify their stability.
• I have added an entry in ./changelog/fragments using the changelog tool.

## Disruptive User Impact
## Author's Checklist

How to test this PR locally

Run the tests

cd metricbeat/module/aerospike
go test -tags=integration -v -count=1 ./...

Or, try running the container:

docker compose up

Related issues

• Closes Metricbeat aerospike module - Go and Python integration tests #47681

## Use cases
## Screenshots
## Logs

---

This is an automatic backport of pull request #47682 done by Mergify.

[mergify]

Cherry-pick of 3d17cad has failed:

On branch mergify/bp/7.17/pr-47682
Your branch is up to date with 'origin/7.17'.

You are currently cherry-picking commit 3d17cad1a.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   metricbeat/module/aerospike/docker-compose.yml

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[botelastic]

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[belimawr]

Interestingly this is passing when I run locally 🤔

[belimawr]

For some odd reason the test seems to be failing to find the aerospike docker image, but it works locally. I'll try re-running it.