feat!: remove "turn on nested replies" feature

Nested replies have been enabled globally for a long time, so this
feature is no longer necessary.

Bug: twpowertools:124
Change-Id: I2938dbcc75f1b7838fe503a6dd9202dde03d04e2
diff --git a/src/common/optionsPrototype.ts b/src/common/optionsPrototype.ts
index 620158b..6ba534a 100644
--- a/src/common/optionsPrototype.ts
+++ b/src/common/optionsPrototype.ts
@@ -180,11 +180,6 @@
     context: "experiments",
     killSwitchType: "experiment",
   },
-  nestedreplies: {
-    defaultValue: false,
-    context: "experiments",
-    killSwitchType: "experiment",
-  },
 
   // Internal options:
   ccdarktheme_switch_enabled: {
@@ -235,4 +230,9 @@
     context: "deprecated",
     killSwitchType: "deprecated",
   },
+  nestedreplies: {
+    defaultValue: false,
+    context: "deprecated",
+    killSwitchType: "deprecated",
+  },
 };
diff --git a/src/contentScripts/communityConsole/start.js b/src/contentScripts/communityConsole/start.js
index c4a3d74..063f58a 100644
--- a/src/contentScripts/communityConsole/start.js
+++ b/src/contentScripts/communityConsole/start.js
@@ -5,15 +5,14 @@
 import ThreadPageDesignWarning from './threadPageDesignWarning.js';
 import WorkflowsImport from './workflows/import.js';
 
-const SMEI_NESTED_REPLIES = 15;
 const SMEI_RCE_THREAD_INTEROP = 22;
 
 getOptions(null).then(options => {
   /* IMPORTANT NOTE: Remember to change this when changing the "ifs" below!! */
   if (options.loaddrafts || options.interopthreadpage ||
-      options.nestedreplies || options.fixpekb269560789) {
+      options.fixpekb269560789) {
     var startup =
-      JSON.parse(document.querySelector('html').getAttribute('data-startup'));
+        JSON.parse(document.querySelector('html').getAttribute('data-startup'));
 
     if (options.fixpekb269560789) {
       if (startup[1]?.[1]?.[8]?.[7]) {
@@ -39,11 +38,6 @@
       }
     }
 
-    if (options.nestedreplies) {
-      if (!startup[1][6].includes(SMEI_NESTED_REPLIES))
-        startup[1][6].push(SMEI_NESTED_REPLIES);
-    }
-
     document.querySelector('html').setAttribute(
         'data-startup', JSON.stringify(startup));
   }
diff --git a/src/static/_locales/en/messages.json b/src/static/_locales/en/messages.json
index 0270096..4c655f7 100644
--- a/src/static/_locales/en/messages.json
+++ b/src/static/_locales/en/messages.json
@@ -171,10 +171,6 @@
     "message": "the new thread page design",
     "description": "Select option added in #interopthreadpage_mode--container, in the options_interopthreadpage string"
   },
-  "options_nestedreplies": {
-    "message": "Turn on the nested replies feature in the Community Console.",
-    "description": "Feature checkbox in the options page"
-  },
   "options_uispacing": {
     "message": "Reduce the whitespace in the Community Console and TW.",
     "description": "Feature checkbox in the options page"
diff --git a/src/static/options/experiments.html b/src/static/options/experiments.html
index 615d5ec..9a21fdf 100644
--- a/src/static/options/experiments.html
+++ b/src/static/options/experiments.html
@@ -15,7 +15,6 @@
         <div id="optional-permissions-warning" hidden data-i18n="optionalpermissionswarning_header"></div>
         <div class="option"><input type="checkbox" id="workflows"> <label for="workflows" data-i18n="workflows"></label> <button id="manage-workflows" data-i18n="workflows_manage"></button></div>
         <div class="option"><input type="checkbox" id="extrainfo"> <label for="extrainfo" data-i18n="extrainfo"></label></div>
-        <div class="option"><input type="checkbox" id="nestedreplies"> <label for="nestedreplies" data-i18n="nestedreplies"></label></div>
         <div class="actions"><button id="save" data-i18n="save"></button></div>
       </form>
       <div id="save-indicator"></div>