kgateway version

v2.2.1

Is your feature request related to a problem? Please describe.

the Opentelemetry AnyValue implementation used in access log configuration
currently supports only StringValue but does not support ArrayValue or
KvListValue.

there is a TODO in listener_policy_types.go indicating that support for
ArrayValue and KvListValue is not yet implemented.

Describe the solution you'd like

extend AnyValue support in access log configuration to include:

• ArrayValue
• KvListValue

Describe alternatives you've considered

No response

Additional Context

the OpenTelemetry specification for AnyValue includes support for
string, bool, int, double, array, and key-value list types.
implementing ArrayValue and KvListValue would complete support for
structured attribute types in access log configuration.