OSSM-5444: Fix mapping spec.tracing.type: None to helm values

[jewertow]

When I was testing zipkin extension provider, I noticed that we incorrectly handle None tracing type and as a result istio proxies receive incorrect default config:

defaultConfig:
  discoveryAddress: istiod-basic.istio-system.svc:15012
  proxyMetadata:
    ISTIO_META_DNS_AUTO_ALLOCATE: "true"
    ISTIO_META_DNS_CAPTURE: "true"
    PROXY_XDS_VIA_AGENT: "true"
  tracing: null

and therefore pilot-agent overwrites tracing: null with the default zipkin address, while the expected config is:

defaultConfig:
  discoveryAddress: istiod-basic.istio-system.svc:15012
  proxyMetadata:
    ISTIO_META_DNS_AUTO_ALLOCATE: "true"
    ISTIO_META_DNS_CAPTURE: "true"
    PROXY_XDS_VIA_AGENT: "true"
  tracing: {}

Actually, it does not affect tracing, because when a Telemetry config is applied to a proxy, the default tracing address is not used by Envoy, but it might be confusing when debugging tracing issues.

[yxun]

I feel it's better comment out the line 405 and keep the comment lines 406-413 for tlsSettings example references

[jewertow]

I removed these values, because they are obsolete and no longer used in the charts.