[Azure SRE Agent][All & Namespace] Calling tool `sreagent_incidents_plans_create` failed

**Description:**
In `Namespace` and `All` mode, testing prompts related to [Azure SRE Agent](https://github.com/microsoft/mcp/blob/main/servers/Azure.Mcp.Server/docs/e2eTestPrompts.md#azure-sre-agent), with prompt `Enable a new incident response plan on SRE Agent with alert filter and handler`, it returns `Service Unavailable`:

**Steps to Reproduce:**
1. Start mcp server in `Namespace` mode or `All` tools mode.
2. Open GitHub Copilot in VS Code and [switch to Agent mode](https://code.visualstudio.com/docs/copilot/chat/chat-agent-mode).
3. Enter the test prompt.

**Environment:**
- OS: Windows.
- Vscode Version: 1.134
- Large Language Model: **GPT-5.6 Sol**
- Azure MCP Server: **3.0.37**

**Expected Behavior:**
Tool `sreagent_incidents_plans_create` can succeed.

@RickWinter and @g2vinay for notification