libbeat/common/transport: fix log message about TLS

[belimawr]

What does this PR do?

This commit fixes the log message issued by the test output command.
Our current TLS verification relies on more than the value of
tlsConfig.InsecureSkipVerify, so the previous implementation would
log that TLS was disabled when it was not.

This commit fixes it by checking the value of config.Verification.

Why is it important?

It fixes a logging issue

Checklist

• [ x ] My code follows the style guidelines of this project
• [ x ] 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
• [ x ] I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Author's Checklist

• Should we add some tests to the bug reported on the issues below?
  Agent [master]: dev, snapshot build crashes on start on Windows  #30315
  Missing TLS configuration causes agent crash on Windows #30314

How to test this PR locally

To test using Filebeat, set the ssl.verification_mode on any Beat output to anything other than none, then run filebeat test output. You should see the correct log message based on the verification mode you set.

Related issues

• Relates Agent [master]: dev, snapshot build crashes on start on Windows  #30315
• Duplicates/Fixes libbeat/common/transport: fix log message about TLS #30063

## Use cases
## Screenshots

Logs

elasticsearch: https://somewhere-in-the-cloud:443...
  parse url... OK
  connection...
    parse host... OK
    dns lookup... OK
    addresses: 42.42.42.42 42.42.42.43
    dial up... OK
  TLS...
    security: server's certificate chain verification is enabled
    handshake... OK
    TLS version: TLSv1.2
    dial up... OK
  talk to server... OK
  version: 7.17.0

[mergify]

This pull request does not have a backport label. Could you fix it @belimawr? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v./d./d./d is the label to automatically backport to the 7./d branch. /d is the digit

NOTE: backport-skip has been added to this pull request.

[elasticmachine]

💚 Build Succeeded

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Start Time: 2022-02-10T17:03:24.278+0000

• Duration: 112 min 24 sec

Test stats 🧪

Test	Results
Failed	0
Passed	48172
Skipped	4379
Total	52551

💚 Flaky test report

Tests succeeded.

🤖 GitHub comments

To re-run your PR in the CI, just comment with:

• /test : Re-trigger the build.

• /package : Generate the packages and run the E2E tests.

• /beats-tester : Run the installation tests with beats-tester.

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

[belimawr]

/test

[belimawr]

rebase onto main, force-push

[belimawr]

/test

[elasticmachine]

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

[cmacknz]

Did we sanity check this on Windows 10 specifically to ensure the issue with the original change is fixed?

[belimawr]

Did we sanity check this on Windows 10 specifically to ensure the issue with the original change is fixed?

The issue wasn't Windows-specific, I believe some Windows tests triggered it first or they have a different test suit that triggered the bug.

[belimawr]

Anyway, I'll try to test it on Windows before merging this PR.