Use same logic as Go SDK for DatabricksConfig.isAzure() (#174)

## Changes
The current isAzure() logic only checks if ".azuredatabricks." is
contained in the hostname, which fails for workspaces in other Azure
environments. This PR copies the logic directly from the Go SDK:
https://github.com/databricks/databricks-sdk-go/blob/main/config/config.go#L142

## Tests
- [x] Some unit tests ensuring that isAzure() returns the right values
for various hosts, including AWS, Azure public, Azure US Gov, and Azure
China.

Author: mgyucht

databricks-sdk-java/src/main/java/com/databricks/sdk/core/DatabricksConfig.java

@@ -463,7 +463,9 @@ public boolean isAzure() {
     if (host == null) {
       return false;
     }
-    return host.contains(".azuredatabricks.");
+    return host.contains(".azuredatabricks.net")
+        || host.contains("databricks.azure.cn")
+        || host.contains(".databricks.azure.us");
   }
 
   public synchronized void authenticate(HttpMessage request) {

databricks-sdk-java/src/test/java/com/databricks/sdk/core/AzureCliCredentialsProviderTest.java

@@ -86,7 +86,7 @@ void testFallbackWhenTailsToGetTokenForSubscription() {
   void testGetTokenWithoutWorkspaceResourceID() {
     AzureCliCredentialsProvider provider = getAzureCliCredentialsProvider(mockTokenSource());
     DatabricksConfig config =
-        new DatabricksConfig().setHost(".azuredatabricks.").setCredentialsProvider(provider);
+        new DatabricksConfig().setHost(".azuredatabricks.net").setCredentialsProvider(provider);
 
     ArgumentCaptor<List<String>> argument = ArgumentCaptor.forClass(List.class);
 

databricks-sdk-java/src/test/java/com/databricks/sdk/core/DatabricksConfigTest.java

@@ -25,4 +25,28 @@ public void testIsAccountHostWorkspace() {
     assertFalse(
         new DatabricksConfig().setHost("https://westeurope.azuredatabricks.net").isAccountClient());
   }
+
+  @Test
+  public void testIsAzureForAwsHost() {
+    assertFalse(
+        new DatabricksConfig().setHost("https://my-workspace.cloud.databricks.com/").isAzure());
+  }
+
+  @Test
+  public void testIsAzurePublic() {
+    assertTrue(
+        new DatabricksConfig().setHost("https://adb-1234567890.0.azuredatabricks.net/").isAzure());
+  }
+
+  @Test
+  public void testIsAzureMooncake() {
+    assertTrue(
+        new DatabricksConfig().setHost("https://adb-1234567890.0.databricks.azure.cn/").isAzure());
+  }
+
+  @Test
+  public void testIsAzureUsGov() {
+    assertTrue(
+        new DatabricksConfig().setHost("https://adb-1234567890.0.databricks.azure.us/").isAzure());
+  }
 }

databricks-sdk-java/src/test/java/com/databricks/sdk/core/oauth/AzureServicePrincipalCredentialsProviderTest.java

@@ -44,7 +44,7 @@ void testGetToken() {
         getAzureServicePrincipalCredentialsProvider(mockTokenSource());
     DatabricksConfig config =
         new DatabricksConfig()
-            .setHost(".azuredatabricks.")
+            .setHost(".azuredatabricks.net")
             .setCredentialsProvider(provider)
             .setAzureClientId("clientID")
             .setAzureClientSecret("clientSecret")