Prevent starting bulk migration search without selected sources

CHANGELOG.md

@@ -34,6 +34,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - (**Migration**) Fix duplicated search matches after resuming the migration search
 - (**Migration**) Fix search progress not getting updated after a manual search
 - (**Migration**) Fix going back to the migration page after a manual search with a changed search string
+- (**Migration**) Fix being able to start search without selected destination sources
 - (**Reader**) Fix scrollbar appearing with "fit to widt/height/screen" page scale mode and applied safe area insets
 - (**Reader**) Fix wrongly positioned mobile progress bar current page indicator
 - (**Reader**) Fix mobile progress bar previous/next chapter button visibility on hover and while disabled

src/features/migration/screens/MigrationSelectDestinationSources.tsx

@@ -166,6 +166,7 @@ export const MigrationSelectDestinationSources = () => {
             <Fab
                 variant="extended"
                 color="primary"
+                disabled={!selectedItemIds.length}
                 sx={{
                     position: 'fixed',
                     bottom: (theme) => theme.spacing(2),