Update apps/portal/src/app/ai/chat/migrate-from-nebula/page.mdx

Co-authored-by: graphite-app[bot] <96075541+graphite-app[bot]@users.noreply.github.com>
Signed-off-by: samina <[email protected]>

Author: saminacodes

apps/portal/src/app/ai/chat/migrate-from-nebula/page.mdx

@@ -150,7 +150,7 @@ context: {
 <Step title="Session Management">
 - Session ID is now optional and nested within the context object
 - If not provided, a new session will be created automatically
-- Sssions enable conversation continuity
+- Sessions enable conversation continuity
 </Step>
 </Steps>