fix: styling error (limitation of 100 chars per line)

Author: manmohak07

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

@@ -450,7 +450,10 @@ public ManagedChannelImplBuilder defaultLoadBalancingPolicy(String policy) {
         directServerAddress);
     Preconditions.checkArgument(policy != null, "policy cannot be null");
     LoadBalancerProvider provider = LoadBalancerRegistry.getDefaultRegistry().getProvider(policy);
-    Preconditions.checkArgument(provider != null, "No provider available for the '%s' load balancing policy.", policy);
+    Preconditions.checkArgument(
+      provider != null,
+      "No provider available for the '%s' load balancing policy.",
+      policy);
     this.defaultLbPolicy = provider.getPolicyName();
     return this;
   }