Removed old Slack references (#5384)

Author: dyesin

documentation-site/pages/getting-started/learn.mdx

@@ -82,9 +82,6 @@ to learn how to build a simple password generator using Base Web.
 Then It's time for you to build a password generator on your own! If you get stuck, or if you've built something using Base Web,
 please let us know. We're happy to help or feature your application on this website.
 
-You can reach us in our [Slack channel](https://join.slack.com/t/baseui/shared_invite/zt-5f1s4d10-1D2uywAECAG50m64PTH9cw)
-or through [GitHub issues](https://github.com/uber/baseweb/issues).
-
 ### Base Web with data fetching
 
 You can find a more complex application using Base Web [here](https://github.com/tajo/fusion-baseui). It helps you build an application