MM-67510 Drop deprecated autotranslation column from ChannelMembers (#37496)

server/channels/db/migrations/migrations.list

@@ -421,3 +421,7 @@ channels/db/migrations/postgres/000212_add_scheduled_post_recurrence.down.sql
 channels/db/migrations/postgres/000212_add_scheduled_post_recurrence.up.sql
 channels/db/migrations/postgres/000213_add_scheduled_post_pending_index.down.sql
 channels/db/migrations/postgres/000213_add_scheduled_post_pending_index.up.sql
+channels/db/migrations/postgres/000214_drop_channelmembers_autotranslation.down.sql
+channels/db/migrations/postgres/000214_drop_channelmembers_autotranslation.up.sql
+channels/db/migrations/postgres/000215_drop_channelmembers_autotranslation_column.down.sql
+channels/db/migrations/postgres/000215_drop_channelmembers_autotranslation_column.up.sql

server/channels/db/migrations/postgres/000214_drop_channelmembers_autotranslation.down.sql

@@ -0,0 +1,8 @@
+-- morph:nontransactional
+-- Recreate the partial index on the channelmembers autotranslation column,
+-- mirroring migration 000147. Runs after 000215 restores the column.
+-- CONCURRENTLY cannot run inside a transaction, so this must be the only
+-- statement in the file.
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_channelmembers_autotranslation_enabled
+    ON channelmembers (channelid)
+    WHERE autotranslation = true;

server/channels/db/migrations/postgres/000214_drop_channelmembers_autotranslation.up.sql

@@ -0,0 +1,5 @@
+-- morph:nontransactional
+-- Drop the partial index on the deprecated channelmembers autotranslation
+-- column ahead of dropping the column itself in 000215. CONCURRENTLY cannot run
+-- inside a transaction, so this must be the only statement in the file.
+DROP INDEX CONCURRENTLY IF EXISTS idx_channelmembers_autotranslation_enabled;

server/channels/db/migrations/postgres/000215_drop_channelmembers_autotranslation_column.down.sql

@@ -0,0 +1,5 @@
+-- Recreate the deprecated channelmembers autotranslation column, mirroring
+-- migration 000147. Prior values are not restorable. The partial index is
+-- recreated separately in 000214.
+ALTER TABLE channelmembers
+    ADD COLUMN IF NOT EXISTS autotranslation boolean NOT NULL DEFAULT false;

server/channels/db/migrations/postgres/000215_drop_channelmembers_autotranslation_column.up.sql

@@ -0,0 +1,5 @@
+-- Drop the deprecated channelmembers autotranslation column (opt-in semantics),
+-- replaced by autotranslationdisabled (opt-out) in migration 000151. The partial
+-- index on this column is dropped separately in 000214.
+ALTER TABLE channelmembers
+    DROP COLUMN IF EXISTS autotranslation;