Remove the env check

The env check is not needded anymore as all the commands rely on the
env files having already been created remotely.

The only place the env is needed is when running `kamal env push` and
that will still raise an apropriate error.

lib/kamal/cli/base.rb

@@ -75,8 +75,6 @@ module Kamal::Cli
       def mutating
         return yield if KAMAL.holding_lock?
 
-        KAMAL.config.ensure_env_available
-
         run_hook "pre-connect"
 
         ensure_run_directory

lib/kamal/configuration.rb

@@ -204,13 +204,6 @@ class Kamal::Configuration
     ensure_destination_if_required && ensure_required_keys_present && ensure_valid_kamal_version
   end
 
-  # Will raise KeyError if any secret ENVs are missing
-  def ensure_env_available
-    roles.collect(&:env_file).each(&:to_s)
-
-    true
-  end
-
   def to_h
     {
       roles: role_names,