Only show Troubleshoot/Inspect with AI button if installation has mcp-kubernetes

[marians]

We have installations without mcp-kubernetes. For resources on these installation, we should not show the Inspect/Troubleshoot with AI button, to avoid a frustrating experience.

Also the feature should only be shown in instances that have AI chat enabled at all.

Tasks:

• Hide AI button for resources on installations without mcp-kubernetes
• Make AIChatButton conditionally visible based on ai-chat plugin availability backstage#1302