configuration: handling of default service

[xrmx]

The specs says:

[3] service.name: MUST be the same for all instances of horizontally scaled services. If the value was not specified, SDKs MUST fallback to unknown_service: concatenated with the process executable name, e.g. unknown_service:bash.

I think on the configuration side we are just setting unknown_service while in sdk's Resource.create we are doing that correctly.

[saisharan0103]

The mismatch seems centered on configuration defaulting service.name to plain unknown_service, while Resource.create already applies the spec form with the executable suffix. For a PR, I would start by tracing the configuration path that materializes the default resource attributes and make it share or mirror the SDK fallback behavior. The regression test should cover an unspecified service.name through configuration and assert the resulting value follows unknown_service:<process executable name>, not just unknown_service.