feat(cli): update secrets --account flag as optional depending on adapter

lib/kamal/secrets/adapters/base.rb

@@ -1,13 +1,20 @@
 class Kamal::Secrets::Adapters::Base
   delegate :optionize, to: Kamal::Utils
 
-  def fetch(secrets, account:, from: nil)
+  def fetch(secrets, account: nil, from: nil)
+    raise RuntimeError, "Missing required option '--account'" if requires_account? && account.blank?
+
     check_dependencies!
+
     session = login(account)
     full_secrets = secrets.map { |secret| [ from, secret ].compact.join("/") }
     fetch_secrets(full_secrets, account: account, session: session)
   end
 
+  def requires_account?
+    true
+  end
+
   private
     def login(...)
       raise NotImplementedError