add compressed snapshot limitation (#10378)

Signed-off-by: Jugal Chauhan <[email protected]>

Author: jugal-chauhan

_migration-assistant/overview/is-migration-assistant-right-for-you.md

@@ -164,6 +164,7 @@ To use `Reindex-from-Snapshot` (RFS), ensure the following:
   - `include_global_state: true` – Ensures that global cluster state is included.
   - `compress: false` – Disables metadata compression, which is required for compatibility with RFS.
 - Shards of up to **80 GiB** are supported by default. Larger shard sizes can be configured, **except in AWS GovCloud (US)**, where 80 GiB is the maximum.
+- Snapshots using `zstd` compression are not supported for migration. If compression is needed, use the default `LZ4` format instead.
 
 ### Capture and Replay