[7.x](backport #27109) [Filebeat] decode_cef - allow MACs without separators

[mergify]

This is an automatic backport of pull request #27109 done by Mergify.

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[elasticmachine]

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• Start Time: 2021-08-02T14:13:19.173+0000

• Duration: 96 min 52 sec

• Commit: 7ba9dcb

Test stats 🧪

Test	Results
Failed	0
Passed	7448
Skipped	1201
Total	8649

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Test stats 🧪

Test	Results
Failed	0
Passed	7448
Skipped	1201
Total	8649

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b mergify/bp/7.x/pr-27109 upstream/mergify/bp/7.x/pr-27109
git merge upstream/7.x
git push upstream mergify/bp/7.x/pr-27109