[filebeat][fix] remove duplicate nil check in gzipFile

[barkhayot]

• remove duplicate nil check in gzipFile

[github-actions]

🤖 GitHub comments

Just comment with:

• run docs-build : Re-trigger the docs validation. (use unformatted text in the comment!)

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: acbe62cc-d159-419d-b61c-17a225fdcae3

📥 Commits

Reviewing files that changed from the base of the PR and between 12e4652 and ada16c5.

📒 Files selected for processing (1)

• filebeat/beater/diagnostics.go

---

📝 Walkthrough

Walkthrough

The gzipFile function in filebeat/beater/diagnostics.go was refactored to simplify error handling for the io.Copy call. A redundant nested if err != nil check was removed, replacing it with a direct return statement that wraps the error using fmt.Errorf. The change reduces code by two net lines and maintains equivalent functionality with cleaner error handling logic.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

• 🛠️ Update Documentation: Commit on current branch
• 🛠️ Update Documentation: Create PR

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[mergify]

This pull request does not have a backport label.
If this is a bug or security fix, could you label this PR @barkhayot? 🙏.
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-8./d is the label to automatically backport to the 8./d branch. /d is the digit
• backport-active-all is the label that automatically backports to all active branches.
• backport-active-8 is the label that automatically backports to all active minor branches for the 8 major.
• backport-active-9 is the label that automatically backports to all active minor branches for the 9 major.

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)