Remove redundant skip deletion in count query (code review fix)

Co-authored-by: xuyushun441-sys <255036401+xuyushun441-sys@users.noreply.github.com>

Author: Copilot

packages/runtime/server/test/rest-advanced.test.ts

@@ -90,7 +90,6 @@ class MockDriver implements Driver {
         // Count should not apply offset/limit, only filters
         const countQuery = { ...query };
         delete countQuery.offset;
-        delete countQuery.skip;
         delete countQuery.top;
         delete countQuery.limit;
         const items = await this.find(objectName, countQuery);