Keys containing __proto__ are handled inconsistently

[alxndrsn]

Reporting a bug?

PR demonstrating inconsistencies at #1705

Expected behavior

Either:

1. treat keys containing __proto__ this same as any other key, or
2. reject any key containing __proto__

Reproduction

#1705

System Info

N/A

Screenshot

No response

Additional context

Currently the only mention of __proto__ in this repo is at:

vue-i18n/src/install.js

Line 33 in 6895542

// use simple mergeStrategies to prevent i18n instance lose '__proto__'

Validations

• Read the Contributing Guidelines
• Read the Documentation
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion
• The provided reproduction is a minimal reproducible example of the bug.