K8s: server_address not properly replaced in Beyla 1.9

[mariomac]

The server_address field often contains an IP instead of the Kubernetes entity/service.

This worked in Beyla 1.8.

[grcevski]

I wonder if it's an edge case of the environment variable reading, maybe we read something empty and we don't report an error in the logic, causing us to not go down the route to read the k8s data.

[marctc]

This worked in Beyla 1.8.

This is being an ongoing issue from before. See #933

[bjor-joh]

To me this issue is a lot more apparent in 1.9.
I bumped to chart version 1.5.0 and 95% of all metrics got an ip in the server_address field.
Once I reverted to 1.4.13 it started working again