Automatic channel category sorting (#30866)

* Automatic channel category sorting

* Fix types

* AIed

* Fix issue where categories are updated for all users

* Move all logic to server, clean up

* PR feedback

* Fix lint

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/db/migrations/mysql/000138_add_default_category_name_to_channel.down.sql

@@ -0,0 +1,14 @@
+SET @preparedStatement = (SELECT IF(
+    EXISTS(
+        SELECT 1 FROM INFORMATION_SCHEMA.STATISTICS
+        WHERE table_name = 'Channels'
+        AND table_schema = DATABASE()
+        AND column_name = 'DefaultCategoryName'
+    ),
+    'ALTER TABLE Channels DROP COLUMN DefaultCategoryName;',
+    'SELECT 1;'
+));
+
+PREPARE removeColumnIfExists FROM @preparedStatement;
+EXECUTE removeColumnIfExists;
+DEALLOCATE PREPARE removeColumnIfExists;

server/channels/db/migrations/mysql/000138_add_default_category_name_to_channel.up.sql

@@ -0,0 +1,14 @@
+SET @preparedStatement = (SELECT IF(
+    NOT EXISTS(
+        SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS
+        WHERE table_name = 'Channels'
+        AND table_schema = DATABASE()
+        AND column_name = 'DefaultCategoryName'
+    ),
+    'ALTER TABLE Channels ADD COLUMN DefaultCategoryName varchar(64) NOT NULL DEFAULT "";',
+    'SELECT 1;'
+));
+
+PREPARE addColumnIfNotExists FROM @preparedStatement;
+EXECUTE addColumnIfNotExists;
+DEALLOCATE PREPARE addColumnIfNotExists;