[3.1] Updated the social icons: Twitter/X and Google Groups

[vamera]

Description

This PR updates the social Icons in our theme, especially the ones for X (Twitter) and Google Groups.

Checks

Docs building

• [x] Compiles without warnings.

Code formatting and web optimization

• [ ] Uses three spaces indentation.
• [ ] Adds or updates meta descriptions accordingly.
• [ ] Updates the redirects.js script if necessary (check this guide).

Writing style

• [ ] Uses present tense, active voice, and semi-formal registry.
• [ ] Uses short, simple sentences.
• [ ] Uses bold for user interface elements, italics for key terms or emphasis, and code font for Bash commands, file names, REST paths, and code.