core: Align channel startup queuing delay type to connecting per gRFC A121 spec

Author: AgraVator

core/src/main/java/io/grpc/internal/DelayedClientTransport.java

@@ -366,7 +366,7 @@ public InternalLogId getLogId() {
 
   private static String determineQueuingDelayType(@Nullable PickResult pickResult) {
     if (pickResult == null) {
-      return "client_channel_init";
+      return "connecting";
     }
     if (pickResult.getSubchannel() != null) {
       return "subchannel_state_mismatch";
@@ -377,7 +377,7 @@ private static String determineQueuingDelayType(@Nullable PickResult pickResult)
     if (pickResult.getDelayType() != null) {
       return pickResult.getDelayType();
     }
-    return "client_channel_init";
+    return "connecting";
   }
 
   private static String determineQueuingDelayReason(@Nullable PickResult pickResult) {

core/src/test/java/io/grpc/internal/DelayedClientTransportTest.java

@@ -879,7 +879,7 @@ public void streamDelayMetrics_channelFallback_clientChannelInit() {
     delayedTransport.newStream(method, headers, callOptions, customTracers);
 
     verify(mockTracer).recordAttemptDelayStart(
-        "client_channel_init", "client channel: created LB policy.");
+        "connecting", "client channel: created LB policy.");
   }
 
   @Test