ChannelRefreshing feature is incompatible with BigtableDataClientFactory

[igorbernstein2]

Repro:

    BigtableDataSettings settings = BigtableDataSettings.newBuilder()
        .setProjectId(PROJECT_ID)
        .setInstanceId(INSTANCE_ID)
        .setRefreshingChannel(true)
        .build();

    BigtableDataClientFactory f = BigtableDataClientFactory
        .create(settings);

    f.createDefault();

Exception in thread "main" java.lang.IllegalArgumentException: refreshingChannel only works with InstantiatingGrpcChannelProviders
	at com.google.common.base.Preconditions.checkArgument(Preconditions.java:142)
	at com.google.cloud.bigtable.data.v2.stub.EnhancedBigtableStubSettings$Builder.build(EnhancedBigtableStubSettings.java:791)
	at com.google.cloud.bigtable.data.v2.BigtableDataSettings.<init>(BigtableDataSettings.java:71)
	at com.google.cloud.bigtable.data.v2.BigtableDataSettings.<init>(BigtableDataSettings.java:63)
	at com.google.cloud.bigtable.data.v2.BigtableDataSettings$Builder.build(BigtableDataSettings.java:363)
	at com.google.cloud.bigtable.data.v2.BigtableDataClientFactory.createDefault(BigtableDataClientFactory.java:115)