Add telemetry for tool usage from the `dart mcp-server` command

[kenzieschmoll]

draft pr for unified_analytics here: dart-lang/tools#2112

[bkonyi]

What sort of telemetry are you looking for? The number of invocations of dart mcp-server? We already collect data for high-level command usage details.

[kenzieschmoll]

We are interested in collecting data on which tools are being called and from which clients.