Fix encoding of Brazilian Portuguese localization

[basil]

#8543 (accidentally?) changed the encoding of a Brazilian Portuguese localization from UTF-8 to ISO-8859-1. As of a few months back we have been trying to keep all properties files in UTF-8.

Testing done

$ file core/src/main/resources/jenkins/monitor/JavaVersionRecommendationAdminMonitor/description_pt_BR.properties 
core/src/main/resources/jenkins/monitor/JavaVersionRecommendationAdminMonitor/description_pt_BR.properties: Unicode text, UTF-8 text

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[MarkEWaite]

Thanks for fixing my mistake! I was relying on emacs to preserve all the right things with character sets, but that was obviously not enough.