Fix mastodon:setup choking on env variables containing '%' (#13940)

Fix a regression introduced in #13928, caused by TTY::Command building
shell commands by chaining string substitutions.

Ditch TTY::Command and use system instead (both do shell out).

Gemfile

@@ -94,7 +94,6 @@ gem 'simple_form', '~> 5.0'
 gem 'sprockets-rails', '~> 3.2', require: 'sprockets/railtie'
 gem 'stoplight', '~> 2.2.0'
 gem 'strong_migrations', '~> 0.6'
-gem 'tty-command', '~> 0.9', require: false
 gem 'tty-prompt', '~> 0.21', require: false
 gem 'twitter-text', '~> 1.14'
 gem 'tzinfo-data', '~> 1.2020'

Gemfile.lock

@@ -623,8 +623,6 @@ GEM
     thwait (0.1.0)
     tilt (2.0.10)
     tty-color (0.5.1)
-    tty-command (0.9.0)
-      pastel (~> 0.7.0)
     tty-cursor (0.7.1)
     tty-prompt (0.21.0)
       necromancer (~> 0.5.0)
@@ -792,7 +790,6 @@ DEPENDENCIES
   strong_migrations (~> 0.6)
   thor (~> 0.20)
   thwait (~> 0.1.0)
-  tty-command (~> 0.9)
   tty-prompt (~> 0.21)
   twitter-text (~> 1.14)
   tzinfo-data (~> 1.2020)

lib/tasks/mastodon.rake

@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require 'tty-command'
 require 'tty-prompt'
 
 namespace :mastodon do
@@ -334,8 +333,6 @@ namespace :mastodon do
       prompt.say 'This configuration will be written to .env.production'
 
       if prompt.yes?('Save configuration?')
-        cmd = TTY::Command.new(printer: :quiet)
-
         env_contents = env.each_pair.map do |key, value|
           if value.is_a?(String) && value =~ /[\s\#\\"]/
             if value =~ /[']/
@@ -367,7 +364,7 @@ namespace :mastodon do
           prompt.say 'Running `RAILS_ENV=production rails db:setup` ...'
           prompt.say "\n\n"
 
-          if cmd.run!(env.merge({ RAILS_ENV: 'production', SAFETY_ASSURED: 1 }), :rails, 'db:setup').failure?
+          if !system(env.transform_values(&:to_s).merge({ 'RAILS_ENV' => 'production', 'SAFETY_ASSURED' => '1' }), 'rails db:setup')
             prompt.error 'That failed! Perhaps your configuration is not right'
           else
             prompt.ok 'Done!'
@@ -382,7 +379,7 @@ namespace :mastodon do
           prompt.say 'Running `RAILS_ENV=production rails assets:precompile` ...'
           prompt.say "\n\n"
 
-          if cmd.run!(env.merge({ RAILS_ENV: 'production' }), :rails, 'assets:precompile').failure?
+          if !system(env.transform_values(&:to_s).merge({ 'RAILS_ENV' => 'production' }), 'rails assets:precompile')
             prompt.error 'That failed! Maybe you need swap space?'
           else
             prompt.say 'Done!'