Add GitLab Preview Form (#29804)

Author: markazerdd

content/en/dora_metrics/setup/deployments.md

@@ -213,7 +213,7 @@ To confirm that the setup is valid, select your GitHub application in the [GitHu
 {{% /tab %}}
 
 {{% tab "GitLab" %}}
-<div class="alert alert-warning">Datadog's GitLab integration is in Preview. To request access to Datadog's GitLab integration for your organization, reach out to <a href="https://www.datadoghq.com/support/">Datadog Support</a>.</div>
+<div class="alert alert-warning">Repositories from GitLab instances are supported in closed Preview. <a href="https://www.datadoghq.com/product-preview/gitlab-source-code-integration/">Join the Preview</a>.</div>
 
 After your organization has access, follow the [GitLab installation guide][1].