Always add proxy.address tag for the client metrics

[violetagg]

When there is no proxy add na as a value tag.

Fixes #3218

[pderop]

in MicrometerChannelMetricsRecorder.java, line 176, is the following method still used ? if not, can we remove it ?

	@Nullable
	public final Timer getTlsHandshakeTimer(String name, @Nullable String address, String status) {
		MeterKey meterKey = new MeterKey(null, address, null, null, status);
		return MapUtils.computeIfAbsent(tlsHandshakeTimeCache, meterKey,
				key -> filter(Timer.builder(name)
				                   .tags(REMOTE_ADDRESS, address, STATUS, status)
				                   .register(REGISTRY)));
	}

[violetagg]

in MicrometerChannelMetricsRecorder.java, line 176, is the following method still used ? if not, can we remove it ?

	@Nullable
	public final Timer getTlsHandshakeTimer(String name, @Nullable String address, String status) {
		MeterKey meterKey = new MeterKey(null, address, null, null, status);
		return MapUtils.computeIfAbsent(tlsHandshakeTimeCache, meterKey,
				key -> filter(Timer.builder(name)
				                   .tags(REMOTE_ADDRESS, address, STATUS, status)
				                   .register(REGISTRY)));
	}

It is not used, unfortunately the class/method is public and we cannot remove it. May be just deprecate it as unused?

[pderop]

yes, indeed, it can't be removed, in this case, we can deprecate it.

[violetagg]

please check the new commit

[violetagg]

@pderop Thanks for the review!