Revert "FIXUP wip: notifications on starting progress"

This reverts commit 91b9e5402e.

backend/models/image.go

@@ -130,14 +130,6 @@ func (m ImageModel) FinishProcessing(ctx context.Context, imageId uuid.UUID) (mo
 	return userImage, err
 }
 
-func (m ImageModel) StartProcessing(ctx context.Context, processingImageId uuid.UUID) error {
-	startProcessingStmt := UserImagesToProcess.UPDATE(UserImagesToProcess.Status).SET(model.Progress_InProgress)
-
-	_, err := startProcessingStmt.ExecContext(ctx, m.dbPool)
-
-	return err
-}
-
 func (m ImageModel) Get(ctx context.Context, imageId uuid.UUID) (ImageData, error) {
 	getImageStmt := SELECT(UserImages.AllColumns, Image.AllColumns).
 		FROM(