Clean up cloud_chat (elastic#194571)

## Summary

Close elastic/kibana-team#1017

This PR removes the unused Cloud Chat functionality from Kibana. The
chat was not used for some time. Moreover, we've seen some issues with
it where users saw it when it wasn't expected. Given the absence of
automated tests and the fact that the feature is no longer needed, we
are removing it to improve the overall maintainability and reliability
of the codebase. This will also decrease the amount of code loaded for
trial users of Kibana in cloud making the app slightly faster.

.buildkite/scripts/steps/storybooks/build_and_upload.ts

@@ -18,7 +18,6 @@ const STORYBOOKS = [
   'canvas',
   'cases',
   'cell_actions',
-  'cloud_chat',
   'coloring',
   'chart_icons',
   'content_management_examples',

docs/developer/plugin-list.asciidoc

@@ -487,7 +487,8 @@ The plugin exposes the static DefaultEditorController class to consume.
 
 
 |{kib-repo}blob/{branch}/x-pack/plugins/cloud_integrations/cloud_chat/README.md[cloudChat]
-|Integrates with DriftChat in order to provide live support to our Elastic Cloud users. This plugin should only run on Elastic Cloud.
+|The plugin was meant to integrate with DriftChat in order to provide live support to our Elastic Cloud users.
+It was removed, but the plugin was left behind to register no longer used config keys.
 
 
 |{kib-repo}blob/{branch}/x-pack/plugins/cloud_integrations/cloud_data_migration/README.md[cloudDataMigration]

packages/kbn-optimizer/limits.yml

@@ -11,7 +11,6 @@ pageLoadAssetSize:
   cases: 180037
   charts: 55000
   cloud: 21076
-  cloudChat: 19894
   cloudDataMigration: 19170
   cloudDefend: 18697
   cloudExperiments: 109746

src/dev/storybook/aliases.ts

@@ -16,7 +16,6 @@ export const storybookAliases = {
   canvas: 'x-pack/plugins/canvas/storybook',
   cases: 'packages/kbn-cases-components/.storybook',
   cell_actions: 'packages/kbn-cell-actions/.storybook',
-  cloud_chat: 'x-pack/plugins/cloud_integrations/cloud_chat/.storybook',
   cloud: 'packages/cloud/.storybook',
   coloring: 'packages/kbn-coloring/.storybook',
   language_documentation_popover: 'packages/kbn-language-documentation/.storybook',

test/plugin_functional/config.ts

@@ -59,8 +59,6 @@ export default async function ({ readConfigFile }: FtrConfigProviderContext) {
         // We want to test when the banner is shown
         '--telemetry.banner=true',
         // explicitly enable the cloud integration plugins to validate the rendered config keys
-        '--xpack.cloud_integrations.chat.enabled=true',
-        '--xpack.cloud_integrations.chat.chatURL=a_string',
         '--xpack.cloud_integrations.experiments.enabled=true',
         '--xpack.cloud_integrations.experiments.launch_darkly.sdk_key=a_string',
         '--xpack.cloud_integrations.experiments.launch_darkly.client_id=a_string',

test/plugin_functional/test_suites/core_plugins/rendering.ts

@@ -233,8 +233,6 @@ export default function ({ getService }: PluginFunctionalProviderContext) {
         'xpack.cloud.deployments_url (string?)',
         'xpack.cloud.is_elastic_staff_owned (boolean?)',
         'xpack.cloud.trial_end_date (string?)',
-        'xpack.cloud_integrations.chat.chatURL (string?)',
-        'xpack.cloud_integrations.chat.trialBuffer (number?)',
         // Commented because it's inside a schema conditional, and the test is not able to resolve it. But it's shared.
         // Added here for documentation purposes.
         // 'xpack.cloud_integrations.experiments.launch_darkly.client_id (string)',

x-pack/.i18nrc.json

@@ -18,7 +18,6 @@
     "xpack.canvas": "plugins/canvas",
     "xpack.cases": "plugins/cases",
     "xpack.cloud": "plugins/cloud",
-    "xpack.cloudChat": "plugins/cloud_integrations/cloud_chat",
     "xpack.cloudDefend": "plugins/cloud_defend",
     "xpack.cloudLinks": "plugins/cloud_integrations/cloud_links",
     "xpack.cloudDataMigration": "plugins/cloud_integrations/cloud_data_migration",

x-pack/plugins/cloud_integrations/cloud_chat/README.md

@@ -1,3 +1,4 @@
-# Cloud Chat
+# Cloud Chat - Deprecated / Removed
 
-Integrates with DriftChat in order to provide live support to our Elastic Cloud users. This plugin should only run on Elastic Cloud.
+The plugin was meant to integrate with DriftChat in order to provide live support to our Elastic Cloud users.
+It was removed, but the plugin was left behind to register no longer used config keys.

x-pack/plugins/cloud_integrations/cloud_chat/kibana.jsonc

@@ -6,7 +6,7 @@
   "plugin": {
     "id": "cloudChat",
     "server": true,
-    "browser": true,
+    "browser": false,
     "configPath": [
       "xpack",
       "cloud_integrations",