ECOM-412 Set buttons types so enter now triggers register button

lms/templates/student_account/login.underscore

@@ -30,7 +30,7 @@
 
     <%= context.fields %>
 
-    <button class="action action-primary action-update js-login login-button"><%- gettext("Sign in") %></button>
+    <button type="submit" class="action action-primary action-update js-login login-button"><%- gettext("Sign in") %></button>
 
     <div class="login-providers">
         <div class="section-title lines">
@@ -41,7 +41,7 @@
 
         <% _.each( context.providers, function( provider ) {
             if ( provider.loginUrl ) { %>
-                <button type="submit" class="button button-primary button-<%- provider.name %> login-provider login-<%- provider.name %>" data-provider-url="<%- provider.loginUrl %>">
+                <button type="button" class="button button-primary button-<%- provider.name %> login-provider login-<%- provider.name %>" data-provider-url="<%- provider.loginUrl %>">
                     <div class="icon <%- provider.iconClass %>" aria-hidden="true"></div>
                     <%- provider.name %>
                 </button>

lms/templates/student_account/password_reset.underscore

@@ -15,5 +15,5 @@
 
     <%= fields %>
 
-    <button class="action action-primary action-update js-reset"><%- gettext("Reset my password") %></button>
+    <button type="submit" class="action action-primary action-update js-reset"><%- gettext("Reset my password") %></button>
 </form>

lms/templates/student_account/register.underscore

@@ -21,7 +21,7 @@
             <%
             _.each( context.providers, function( provider) {
                 if ( provider.registerUrl ) { %>
-                    <button type="submit" class="button button-primary button-<%- provider.name %> login-provider register-<%- provider.name %>" data-provider-url="<%- provider.registerUrl %>">
+                    <button type="button" class="button button-primary button-<%- provider.name %> login-provider register-<%- provider.name %>" data-provider-url="<%- provider.registerUrl %>">
                         <span class="icon <%- provider.iconClass %>" aria-hidden="true"></span>
                         <%- provider.name %>
                     </button>
@@ -38,7 +38,7 @@
 
     <%= context.fields %>
 
-    <button class="action action-primary action-update js-register register-button"><%- gettext("Create your account") %></button>
+    <button type="submit" class="action action-primary action-update js-register register-button"><%- gettext("Create your account") %></button>
     <p class="note">* <%- gettext("Required field") %></p>
 </form>