Update migration state after locally aborted manga search

In case the search was aborted due to already having found a match, the state was not updated.
Thus, only if the main migration was aborted and not just the "local" manga search, should it exit early on an error.

src/features/migration/MigrationManager.ts

@@ -829,7 +829,7 @@ export class MigrationManager {
                 draft.searchProgress.completed += 1;
             });
         } catch (error) {
-            if (signal.aborted) {
+            if (mainSignal.aborted) {
                 return;
             }