Fixed missing plural message in portuguese validator
merged branch andreabreu98/master (PR #6534)

This PR was submitted for the master branch but it was merged into the 2.1 branch instead (closes #6534).

Commits
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a5e7fdf Fixed missing plural message in portuguese validator

Discussion
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[Validator] Fixed missing plural message

Bug fix: yes
Feature addition: no
Backwards compatibility break: no
Fixes the following tickets: #6151
Todo: -
License of the code: -
Documentation PR: -