Fix resetting skip variable when loading pools from Balancer API

The skip value is used in two ways: To keep track of where in the
  cache the frontend has loaded up to when repeatedly loading from the
cache, or to track where in the API it's up to if loading from the API.

There was a bug where when reading from the API it would call the read
from cache at the end and this would reset the skip variable to the end
of the cache instead of the end of the API list. This meant that when
returning a filtered list of items from the API it would request say
1000 items, but only get 90 (because of the filter), then it would set
set the skip for next time to 1000 (the total requested) when the skip
should have actually been 90.

This fixes that bug by only resetting the skip variable to the requested
skip amount when fetching from the cache. It keeps the skip set to the
total retrieved from the API when results have come from the API.

balancer-js/src/modules/data/pool/balancer-api.ts

@@ -67,7 +67,6 @@ export class PoolsBalancerAPIRepository
     const skip = options?.skip || DEFAULT_SKIP;
 
     const pools = this.pools.slice(skip, first + skip);
-    this.skip = skip + first;
     return pools;
   }
 
@@ -77,7 +76,10 @@ export class PoolsBalancerAPIRepository
       this.pools.length >
         (options?.first || DEFAULT_FIRST) + (options?.skip || DEFAULT_SKIP)
     ) {
-      return this.fetchFromCache(options);
+      const cachedPools = this.fetchFromCache(options);
+      this.skip =
+        (options?.first || DEFAULT_FIRST) + (options?.skip || DEFAULT_SKIP);
+      return cachedPools;
     }
 
     if (this.nextToken) {