Remove backwards compatibility for pg exporter user table stats

The flag postgres_exporter['per_table_stats'] was replaced in
favor of postgres_exporter['flags']['collector.stat_user_tables'].

Deprecation documentation:
  https://docs.gitlab.com/ee/update/deprecations.html#postgres_exporterper_table_stats-configuration-setting

Changelog: removed

Closes https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/8169

files/gitlab-cookbooks/monitoring/attributes/default.rb

@@ -89,7 +89,6 @@ default['monitoring']['postgres_exporter']['flags'] = {
   'collector.postmaster' => true
 }
 default['monitoring']['postgres_exporter']['sslmode'] = nil
-default['monitoring']['postgres_exporter']['per_table_stats'] = nil
 default['monitoring']['postgres_exporter']['consul_service_name'] = 'postgres-exporter'
 default['monitoring']['postgres_exporter']['consul_service_meta'] = nil
 

files/gitlab-cookbooks/monitoring/recipes/postgres-exporter.rb

@@ -35,8 +35,6 @@ postgres_exporter_database = "#{node['gitlab']['gitlab_rails']['db_database']}#{
 
 node.default['monitoring']['postgres_exporter']['env']['DATA_SOURCE_NAME'] = "#{postgres_exporter_connection_string} " \
                                                                              "database=#{postgres_exporter_database}"
-deprecated_per_table_stats = node['monitoring']['postgres_exporter']['per_table_stats']
-node.override['monitoring']['postgres_exporter']['flags']['collector.stat_user_tables'] = deprecated_per_table_stats unless deprecated_per_table_stats.nil?
 include_recipe 'postgresql::user'
 
 # Create log_directory

files/gitlab-cookbooks/package/libraries/deprecations.rb

@@ -341,7 +341,7 @@ module Gitlab
           {
             config_keys: %w(postgres_exporter per_table_stats),
             deprecation: '16.4', # Remove message issue: https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/8170
-            removal: '17.0', # Removal issue: https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/8169
+            removal: '17.0', # Removed in https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/8169. This deprecation entry can be removed after the next upgrade stop.
             note: "Starting with GitLab 17.0, this directive will be controlled by `postgres_exporter['flags'] = { 'collector.stat_user_tables' => bool }`."
           },
           {

spec/chef/cookbooks/monitoring/recipes/postgres_exporter_spec.rb

@@ -151,11 +151,11 @@ RSpec.describe 'monitoring::postgres-exporter' do
       stub_gitlab_rb(
         postgres_exporter: {
           flags: {
-            'some.flag' => 'foo'
+            'some.flag' => 'foo',
+            'collector.stat_user_tables' => true,
           },
           listen_address: 'localhost:9700',
           enable: true,
-          per_table_stats: true,
           sslmode: 'require',
           env: {
             'USER_SETTING' => 'asdf1234'