Fix missing docker staging DRA artifacts

[dliappis]

Proposed commit message

The DRA staging release is failing because the Buildkite step isn't capturing the right artifacts.
This commit fixes the issue by adjusting the artifact_paths to match the other steps.

Logs

Example of failure: https://buildkite.com/elastic/beats-packaging-pipeline/builds/96#018f2e52-8eda-4311-91fc-662353604f29

[mergify]

This pull request does not have a backport label.
If this is a bug or security fix, could you label this PR @dliappis? 🙏.
For such, you'll need to label your PR with:

• The upcoming major version of the Elastic Stack
• The upcoming minor version of the Elastic Stack (if you're not pushing a breaking change)

To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v8./d.0 is the label to automatically backport to the 8./d branch. /d is the digit

[elasticmachine]

💚 Build Succeeded

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Build stats

• Start Time: 2024-04-30T11:20:29.996+0000

• Duration: 15 min 48 sec

Test stats 🧪

Test	Results
Failed	0
Passed	2
Skipped	0
Total	2

💚 Flaky test report

Tests succeeded.

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