doc: Update User Invitation from console

[sravankumar985]

Summary

Currently, the documentation says, that user invitation is not possible from the console. Ref: Inviting Users. This is to update the section with instructions on inviting the users from console.
Inviting Users through console is added in TTS v3.20.1

Ref: https://www.thethingsindustries.com/docs/whats-new/3.20.1/

Details

Screenshots

New:

Changes

Updated the instructions to invite users from the console.

Notes for Reviewers

...

Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Run Locally: Verified that the docs build using make server, posted screenshots, verified external links. Test with HUGO_PARAMS_SEARCH_ENABLED=true if style changes will affect the search bar.
• New Features Marked: Documentation for new features is marked using the new-in-version shortcode, according to the guidelines in CONTRIBUTING.
• Style Guidelines: Documentation obeys style guidelines in CONTRIBUTING.
• Commits: Commit messages follow guidelines in CONTRIBUTING, there are no fixup commits left.

[KrishnaIyer]

Really nice. Thanks