feat: fix getUnspentsForAddresses in BlockchairApi

When we pass an array of addresses we make a single call to the
blockchair API with a comma separated list of addresses. The response
includes the list of all utxos for every address in the list.

Example response

```
  "utxo": [
    {
      "block_id": 838353,
      "transaction_hash": "19a2e26860981413ceab82052738386d72d530333b3a7e0237518e242c65524d",
      "index": 0,
      "value": 42000,
      "address": "34EaQXdjELqWrTFxJWFgmVmF91kPhdP4us"
    },
    {
      "block_id": 838353,
      "transaction_hash": "19a2e26860981413ceab82052738386d72d530333b3a7e0237518e242c65524d",
      "index": 1,
      "value": 657269,
      "address": "bc1qv669qw5tzxsue5qrl36ygqnaahm98n9t68hdz577cz2r8eldyj3q6d90c4"
    }
  ]

```

However, with the code as it is now, for every address we map all the
utxos in the response to the address. In the above example we will have
a return value of an array of size 4 instead of the expected size 2.
Associated unspents to addresses it doesnt belong to.

Ticket: BTC-1084

TICKET: BTC-1084

modules/blockapis/src/impl/BlockchairApi.ts

@@ -37,6 +37,7 @@ type BlockchairUnspent = {
   script_hex: string;
   spending_transaction_hash: string;
   spending_index: number;
+  address: string;
 };
 
 // https://blockchair.com/api/docs#link_300
@@ -144,19 +145,24 @@ export class BlockchairApi implements AddressApi, UtxoApi {
     if (addr.length > 100) {
       throw new Error(`invalid size`);
     }
-    // https://blockchair.com/api/docs#link_300
-    return (
-      await this.get<BlockchairResponse<{ utxo: BlockchairUnspent[] }>>(`/dashboards/addresses/${addr.join(',')}`)
-    ).map((body) => {
-      return addr.flatMap((a) => {
-        return body.data.utxo.map((unspent): Unspent => {
-          return {
-            id: formatOutputId({ txid: unspent.transaction_hash, vout: unspent.index }),
-            address: a,
-            value: unspent.value,
-          };
-        });
-      });
+
+    const response = await this.get<BlockchairResponse<{ utxo: BlockchairUnspent[] }>>(
+      `/dashboards/addresses/${addr.join(',')}`
+    );
+
+    return response.map((body) => {
+      return body.data.utxo
+        .flatMap((unspent): Unspent | undefined => {
+          if (addr.includes(unspent.address)) {
+            return {
+              id: formatOutputId({ txid: unspent.transaction_hash, vout: unspent.index }),
+              address: unspent.address,
+              value: unspent.value,
+            };
+          }
+          return undefined;
+        })
+        .filter((unspent): unspent is Unspent => unspent !== undefined);
     });
   }