Remove line in logs about agents of multiple types (#20071)

Summary:
With agent queues in the mix, this line is misleading.

Test Plan: View docs page

## Summary & Motivation

## How I Tested These Changes

docs/content/dagster-cloud/deployment/agents/running-multiple-agents.mdx

@@ -9,8 +9,6 @@ platform_type: "cloud"
 
 Each Dagster Cloud full deployment (e.g., `prod`) needs to have at least one agent running. A single agent is adequate for many use cases, but you may want to run multiple agents to provide redundancy if a single agent goes down.
 
-It's recommended to only use multiple agents of the same type (e.g. multiple Kubernetes agents).
-
 ---
 
 ## Running multiple agents in the same environment