remove clear_prefix call as it is not required

Author: ParthDesai

runtime/common/src/migrations.rs

@@ -627,20 +627,6 @@ where
 
         log::info!("Migrating {:?} elements", migrated_count);
 
-        // Removing older entries with old location as key
-        let mut removal_result = storage::unhashed::clear_prefix(
-            &ForeignAssetToAssetId::<Runtime>::final_prefix(),
-            None,
-            None,
-        );
-        while removal_result.maybe_cursor.is_some() {
-            removal_result = storage::unhashed::clear_prefix(
-                &ForeignAssetToAssetId::<Runtime>::final_prefix(),
-                None,
-                removal_result.maybe_cursor.as_deref(),
-            );
-        }
-
         // Write to the new storage with removed and added fields
         for (asset_id, old_location) in asset_id_to_foreign_asset_data {
             if let Ok(new_location) = Runtime::ForeignAsset::try_from(old_location) {
@@ -662,7 +648,6 @@ where
         Runtime::DbWeight::get()
             .reads(migrated_count as u64)
             .saturating_add(Runtime::DbWeight::get().writes(migrated_count as u64 + 3u64))
-            .saturating_add(Runtime::DbWeight::get().writes(foreign_asset_to_asset_id_count as u64))
     }
 
     #[cfg(feature = "try-runtime")]