Chore: Remove deprecation warning post rails upgrade (#7080)

Fixes: https://linear.app/chatwoot/issue/CW-1575/fix-deprecations-post-upgrade-to-rails-7

app/views/fields/belongs_to/_index.html.erb

@@ -21,7 +21,7 @@ By default, the relationship is rendered as a link to the associated object.
       field.display_associated_resource,
       super_admin_user_path(field.data),
     ) %>
-  <% elsif valid_action?(:show, field.associated_class) %>
+  <% elsif existing_action?(field.associated_class, :show) %>
     <%= link_to(
       field.display_associated_resource,
       [namespace, field.data],

app/views/fields/belongs_to/_show.html.erb

@@ -16,7 +16,7 @@ By default, the relationship is rendered as a link to the associated object.
 %>
 
 <% if field.data %>
-  <% if valid_action?(:show, field.associated_class) %>
+  <% if existing_action?(field.associated_class, :show) %>
     <%= link_to(
       field.display_associated_resource,
       [namespace, field.data],

app/views/fields/polymorphic/_show.html.erb

@@ -17,7 +17,7 @@ By default, the relationship is rendered as a link to the associated object.
 %>
 
 <% if field.data %>
-  <% if valid_action?(:show, field.data.class) %>
+  <% if existing_action?(field.data.class, :show) %>
     <%= link_to(
       field.display_associated_resource,
       [namespace, field.data],