Adds type attributes for some buttons (#8221)

wagtail/admin/templates/wagtailadmin/account/settings_panels/avatar.html

@@ -12,7 +12,7 @@
             <input type="hidden" name="avatar-avatar-clear" id="avatar-avatar-clear_id">
 
             {% if form.avatar.value %}
-                <button class="avatar-panel__revert-to-gravatar button button-secondary" data-gravatar-url="{% avatar_url request.user 100 gravatar_only=True %}">{% trans "Reset to default" %}</button>
+                <button type="button" class="avatar-panel__revert-to-gravatar button button-secondary" data-gravatar-url="{% avatar_url request.user 100 gravatar_only=True %}">{% trans "Reset to default" %}</button>
             {% endif %}
         </div>
     </div>

wagtail/admin/templates/wagtailadmin/bulk_actions/footer.html

@@ -6,7 +6,7 @@
         <ul class="bulk-actions-buttons">{% bulk_action_choices app_label model_name %}</ul>
         <span data-bulk-action-num-objects class="num-objects"></span>
         {% if objects.has_other_pages %}
-            <button data-bulk-action-num-objects-in-listing class="num-objects-in-listing u-hidden">{{ select_all_obj_text }}</button>
+            <button type="button" data-bulk-action-num-objects-in-listing class="num-objects-in-listing u-hidden">{{ select_all_obj_text }}</button>
         {% endif %}
     </div>
 </section>

wagtail/contrib/forms/templates/wagtailforms/index_submissions.html

@@ -97,7 +97,7 @@
                                 {% include "wagtailadmin/shared/field_as_li.html" with field=field field_classes="field-small" li_classes="col4" %}
                             {% endfor %}
                             <li class="submit col2">
-                                <button name="action" value="filter" class="button button-filter">{% trans 'Filter' %}</button>
+                                <button type="submit" name="action" value="filter" class="button button-filter">{% trans 'Filter' %}</button>
                             </li>
                         </ul>
                     </div>