Bug - Beta inline: fix links

The [inline alert for Beta components](https://github.com/patternfly/patternfly-org/blob/fa02b0e01b46dd03fd3a94478dc8de82e3eca15d/packages/documentation-framework/templates/mdx.js#L76-L87) needs 2 updates:
- Remove the link to the Form (which has been sunsetted and converted to read-only)
- Fix the link for the PatternFly Slack (the correct URL is patternfly.slack.com)