Add example of env expansion with non-standard integer notation

[mx-psi]

Consider the case where the variable HEX_VALUE is set to 0xdeadbeef, and a configuration field such as:

string_field: ${HEX_VALUE}

where string_field has type string on the JSON schema. What should its value be? I am not sure which of the following would be correct per the spec:

1. The string with value 0xdeadbeef (preserving the original presentation format)
2. The string 3735928559 (representing with a standard base 10 format)
3. A type validation error

Having an explicit example of this case on the spec would be useful to understand it.

[trask]

cc @open-telemetry/configuration-maintainers

[mx-psi]

Fixed by #3975