ptBR: catch up with v9.3 (Pixels look, border seams, threat % text, portrait and party target options)

[Barbiero]

Summary

Brings the Brazilian Portuguese locale up to date with v9.3.

• Translates the new Pixels look: border, bar texture, portrait ring, shield, glow line and elite dragon art names
• Border seams and separators on unit frames, nameplates and resource bars; action bar custom borders, textured-border interactions and end caps
• Forever threat % text on nameplates and target/focus frames, plus the reworked Threat Meter's remaining options, slash-command replies and preview
• Portrait outer ring, inner shadow, mirror and non-player portrait options; raid portrait character size; party target options
• Threat Meter and Skyriding HUD rows on the Style page, the style-choice popup footnotes and the Forever style card
• Bag pin/assign menus, the controller "press twice to confirm" prompts, and the sidebar collapse/expand tooltips
• Updates the translation for the reworded CDM button hint
• Removes entries whose English strings no longer exist in the addon (old Threat Meter options, vigor style and nameplate wording)

Test plan

• Checked every added and changed key for duplicates, malformed lines and matching format specifiers
• Confirmed each removed key's English string no longer appears anywhere in the addon source
• Verified official spell/NPC names against Blizzard's pt-BR data