Gray out the password field for admins (#506)

* Gray out the password field for admins

We don't check it for admins since it's not necessary, so ignore it

* Remove the field entirely

core/src/test/java/google/registry/webdriver/RegistrarConsoleScreenshotTest.java

@@ -499,7 +499,6 @@ public class RegistrarConsoleScreenshotTest extends WebDriverTestCase {
 
   @Test
   public void registryLock_unlockModal() throws Throwable {
-    server.setIsAdmin(true);
     server.runInAppEngineEnvironment(
         () -> {
           createDomainAndSaveLock();
@@ -527,7 +526,6 @@ public class RegistrarConsoleScreenshotTest extends WebDriverTestCase {
     driver.findElement(By.id("button-lock-domain")).click();
     driver.waitForElement(By.className("modal-content"));
     driver.findElement(By.id("domain-lock-input-value")).sendKeys("somedomain.tld");
-    driver.findElement(By.id("domain-lock-password")).sendKeys("password");
     driver.diffPage("page");
   }