Drop the residual COPILOT_MODEL test case

Author: simonfaltum

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

@@ -251,19 +251,6 @@ public void testAgentProviderVscodeAgent() {
     Assertions.assertTrue(UserAgent.asString().contains("agent/vscode-agent"));
   }
 
-  @Test
-  public void testAgentProviderCopilotModelAloneNotDetected() {
-    // COPILOT_MODEL is set by Copilot CLI BYOK users and does not by itself
-    // identify any agent.
-    setupAgentEnv(
-        new HashMap<String, String>() {
-          {
-            put("COPILOT_MODEL", "gpt-4");
-          }
-        });
-    Assertions.assertFalse(UserAgent.asString().contains("agent/"));
-  }
-
   @Test
   public void testAgentProviderGoose() {
     setupAgentEnv(