fix: Update Slack channel invite link

[AdarshRawat1]

Pull Request Template

Description

This PR updates the link for the Join Community & Join Slack button to use the correct Slack invitation link instead of the previous channel link. This change ensures new users can join the Slack workspace directly, streamlining the onboarding process.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings
• I have tagged the reviewers in a comment below incase my pull request is ready for a review
• I have signed the commit message to agree to Developer Certificate of Origin (DCO) (to certify that you wrote or otherwise have the right to submit your contribution to the project.) by adding "--signoff" to my git commit command.

[Sonichigo]

LGTM! Thanks for the fix @AdarshRawat1