Fix grammar and syntax issues in pt-PT translations

[alisonborba]

📌 Description

This PR fixes grammatical, spelling, and syntax issues in the Brazilian Portuguese (pt-PT) translations for some interface strings in Uniswap.

🛠️ Changes

• Changed "Mensagens" to "Mensagem" to match singular context
• Replaced verb "Rotear" with noun "Rota"
• Standardized "Confirmar cancelamento" for clarity
• Fixed typo in "fazer swap"

🧪 Testing

All updated strings were visually checked in the local UI. No functional changes introduced.