DASHBOARD__MCP__DISABLED true doesn't disable unsecured warnings

[eerhardt]

Setting DASHBOARD__MCP__DISABLED=true still shows the following message in the dashboard:

and in the console logs:

warn: Aspire.Dashboard.DashboardWebApplication[0]
      MCP server is unsecured. Untrusted apps can access sensitive information.

We shouldn't show these messages when the MCP endpoint is disabled.

[MihuBot]

I'm a bot. Here is a possible duplicate issue (I may be wrong):

• Dashboard warns about unsecured MCP, despite MCP being disabled #12927