fix(db): Make snapshot_recovery migration backward-compatible (#961)

## What ❔

Creates a new DB migration that restores removed snapshot_recovery
columns.

## Why ❔

Having non-backward-compatible change leads to potential breaks on
various environments.

## Checklist

- [x] PR title corresponds to the body of PR (we generate changelog
entries from PRs).

core/lib/dal/migrations/20240129133815_revert_removing_snapshot_recovery_columns.down.sql

@@ -0,0 +1,3 @@
+ALTER TABLE snapshot_recovery
+    DROP COLUMN IF EXISTS last_finished_chunk_id,
+    DROP COLUMN IF EXISTS total_chunk_count;

core/lib/dal/migrations/20240129133815_revert_removing_snapshot_recovery_columns.up.sql

@@ -0,0 +1,5 @@
+-- Temporary revert of the previous `snapshot_recovery` so that the migration is backward-compatible.
+-- Do not use these columns in code.
+ALTER TABLE snapshot_recovery
+    ADD COLUMN IF NOT EXISTS last_finished_chunk_id INT,
+    ADD COLUMN IF NOT EXISTS total_chunk_count INT NOT NULL DEFAULT 0;