refactor(vertexai): remove vertexai/gemini/GetMediaTokenCount.java related to decommissioned generativeaionvertexai_gemini_token_count_advanced region tag (#10299)

* refactor: remove redundant tag from GetMediaTokenCount sample

* refactor: remove GetMediaTokenCount sample from vertexai snippets

* test: remove testMediaTokenCount from SnippetsIT.java

Author: Kef131

vertexai/snippets/src/main/java/vertexai/gemini/GetMediaTokenCount.java

@@ -166,12 +166,6 @@ public void testTokenCount() throws Exception {
     assertThat(tokenCount).isEqualTo(6);
   }
 
-  @Test
-  public void testMediaTokenCount() throws Exception {
-    int tokenCount = GetMediaTokenCount.getMediaTokenCount(PROJECT_ID, LOCATION, GEMINI_FLASH);
-    assertThat(tokenCount).isNotNull();
-  }
-
   @Test
   public void testFunctionCalling() throws Exception {
     String textPrompt = "What's the weather in Paris?";