Log all possible exceptions from Db LB service discovery

What does this MR do and why?

This is the first step in solving #364370 (closed). It aims to get more exposure on the exceptions, which might be killing the Thread which performs DB LB service discovery every ~60+ secs.

Refer #364370 (comment 1382678810) for more context, also this will get removed in !120173 (closed) once we get enough data.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #364370 (closed)