fix(server): use correct file extension for motion photo videos (#8659)

* fix(server): use mp4 file extension for motion photo videos in archive download

* always use mp4 for videos

* get file extension from originalPath

* remove console log

* store motion assets with mp4 extension

* add migration

* set originalFileName for live photo asset stubs

* leave down migration empty

* only set originalFileName for livePhotoStillAsset

* use separate stub

* shorter stub name

server/src/services/metadata.service.ts

@@ -435,7 +435,7 @@ export class MetadataService {
           checksum,
           ownerId: asset.ownerId,
           originalPath: StorageCore.getAndroidMotionPath(asset, motionAssetId),
-          originalFileName: asset.originalFileName,
+          originalFileName: `${path.parse(asset.originalFileName).name}.mp4`,
           isVisible: false,
           deviceAssetId: 'NONE',
           deviceId: 'NONE',