Prevent accidentally using full Drive URL as folder ID (#144)

* Prevent accidentally using full Drive URL as folder ID

core/src/test/java/google/registry/model/registrar/RegistrarTest.java

@@ -452,6 +452,14 @@ public class RegistrarTest extends EntityTestCase {
         () -> registrar.asBuilder().setAllowedTldsUncached(ImmutableSet.of("bad")));
   }
 
+  @Test
+  public void testFailure_driveFolderId_asFullUrl() {
+    IllegalArgumentException thrown =
+        assertThrows(IllegalArgumentException.class, () -> registrar.asBuilder().setDriveFolderId(
+            "https://drive.google.com/drive/folders/1j3v7RZkU25DjbTx2-Q93H04zKOBau89M"));
+    assertThat(thrown).hasMessageThat().isEqualTo("Drive folder ID must not be a full URL");
+  }
+
   @Test
   public void testFailure_nullEmail() {
     NullPointerException thrown =