move focus and validation logic to an 'activate' method

kitsune/sumo/static/sumo/js/form-wizard-sign-in-step.js

@@ -69,8 +69,7 @@ export class SignInStep extends BaseFormStep {
     this.#formEl.addEventListener("submit", this);
     this.#emailEl.addEventListener("blur", this);
     this.#emailEl.addEventListener("input", this);
-
-    this.#emailEl.focus();
+    this.activate();
   }
 
   disconnectedCallback() {
@@ -80,6 +79,11 @@ export class SignInStep extends BaseFormStep {
     this.#emailEl.removeEventListener("input", this);
   }
 
+  activate() {
+    this.#emailErrorEl.classList.remove("visible");
+    this.#emailEl.focus();
+  }
+
   handleEvent(event) {
     switch (event.type) {
       case "blur": {

kitsune/sumo/static/sumo/js/form-wizard.js

@@ -302,6 +302,7 @@ export class FormWizard extends HTMLElement {
       let name = step.getAttribute("name");
       if (name === activeStep) {
         step.slot = "active";
+        step.activate && step.activate();
       } else {
         step.slot = "";
       }