CLI: Update docs for 'aspire telemetry' renamed to 'aspire otel'

Context

In dotnet/aspire#14599 (targeting 13.2), the aspire telemetry command was renamed to aspire otel (with telemetry kept as a backward-compatible alias).

The subcommands are now:

• aspire otel logs (was aspire telemetry logs)
• aspire otel spans (was aspire telemetry spans)
• aspire otel trace (was aspire telemetry trace)

What needs updating

Any aspire.dev documentation that references aspire telemetry subcommands should use aspire otel as the primary command name. The description was also updated to clarify this is specifically OpenTelemetry data.

The old names still work as aliases, but docs should show the new primary names.