feat: Add external iframe warning to plugin import confirmation

[SameDesu123]

A follow-up to #1055.

PR Checklist

• Have you checked if it works normally in all models? Ignore this if it doesn't use models.
• Have you checked if it works normally in all web, local, and node hosted versions? If it doesn't, have you blocked it in those versions?
• Have you added type definitions?

Description

Problem

The initial implementation of the plugin security warning in #1055 did not account for iframes created dynamically via JavaScript. This allowed certain plugins to bypass the security check.

Solution

This pull request enhances the detection mechanism to identify iframes created programmatically. This ensures that users are properly warned about all plugins that utilize external iframes, strengthening the security of the plugin system.

Key Changes

• Enhanced Iframe Detection: Updated the detection logic to recognize dynamically created iframes.
• Localization: The new warning for external iframes has been added to all supported languages.

UI example

external iframe warn