Default missing type= argument to "registration" in launch:create EPP extension

<launch:create> has an optional type argument, that can take either "application" or "registration":
https://tools.ietf.org/html/rfc8334#section-3.3.1

We get that type via createExtension.get().getCreateType(), where if the type= argument isn't given, the function returns null.

In that case, we need to decide based on the TLD - application for end-date sunrise, and registration for start-date sunrise.

For now we can't do that, because FlowPicker doesn't have access to the TLD information. Until that is fixed we decide as follows:

- landrush and sunrush phases will default to APPLICATION, because there's no possible
registration for it.

- sunrise defaults to REGISTRATION because we're currenly launching start-date sunrise that uses registration.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=189942568

javatests/google/registry/flows/domain/DomainCreateFlowTest.java

@@ -1779,6 +1779,24 @@ public class DomainCreateFlowTest extends ResourceFlowTestCase<DomainCreateFlow,
     assertNoLordn("0000001761376042759136-65535", null);
   }
 
+  /**
+   * Test that missing type= argument on launch create works in start-date sunrise.
+   *
+   * <p>TODO(b/76095570):have the same exact test on end-date sunrise - using the same .xml file -
+   * that checks that an application was created.
+   */
+  @Test
+  public void testSuccess_startDateSunriseRegistration_withEncodedSignedMark_noType()
+      throws Exception {
+    createTld("tld", TldState.START_DATE_SUNRISE);
+    clock.setTo(DateTime.parse("2014-09-09T09:09:09Z"));
+    setEppInput("domain_create_sunrise_encoded_signed_mark_no_type.xml");
+    persistContactsAndHosts();
+    runFlowAssertResponse(loadFile("domain_create_response_encoded_signed_mark_name.xml"));
+    assertSuccessfulCreate("tld", false);
+    assertNoLordn("0000001761376042759136-65535", null);
+  }
+
 
   /** Tests possible confusion caused by the common start-date and end-date sunrise LaunchPhase. */
   @Test