Update agent-tasks REST API intro to reference Copilot cloud agent (#60616)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: timrogers <116134+timrogers@users.noreply.github.com>

Author: Copilot

content/rest/agent-tasks/agent-tasks.md

@@ -1,7 +1,7 @@
 ---
 title: Agent tasks
 shortTitle: Agent tasks
-intro: Use the REST API to manage agent tasks in {% data variables.product.prodname_actions %}.
+intro: Use the REST API to start and manage {% data variables.copilot.copilot_coding_agent %} tasks.
 versions: # DO NOT MANUALLY EDIT. CHANGES WILL BE OVERWRITTEN BY A 🤖
   fpt: '*'
   ghec: '*'