Make Blockstore::get_data_shreds_for_slot() return type consistent

We have several other functions that return data shreds; however, these
other functions map shred::Error to BlockstoreError. Make this function
consistent with those and map the error.

ledger/src/blockstore.rs

@@ -1636,14 +1636,16 @@ impl Blockstore {
         })
     }
 
-    pub fn get_data_shreds_for_slot(
-        &self,
-        slot: Slot,
-        start_index: u64,
-    ) -> std::result::Result<Vec<Shred>, shred::Error> {
+    pub fn get_data_shreds_for_slot(&self, slot: Slot, start_index: u64) -> Result<Vec<Shred>> {
         self.slot_data_iterator(slot, start_index)
             .expect("blockstore couldn't fetch iterator")
-            .map(|data| Shred::new_from_serialized_shred(data.1.to_vec()))
+            .map(|data| {
+                Shred::new_from_serialized_shred(data.1.to_vec()).map_err(|err| {
+                    BlockstoreError::InvalidShredData(Box::new(bincode::ErrorKind::Custom(
+                        format!("Could not reconstruct shred from shred payload: {err:?}"),
+                    )))
+                })
+            })
             .collect()
     }