Update indexer-providers.mdx (#1591)

removing Zettablock as they are no longer providing indexed data for us.

Author: johncanneto

docs/data/indexers/indexer-providers/indexer-providers.mdx

@@ -19,10 +19,6 @@ A network indexing service that provides a toolkit to help get you started worki
 
 An open-source data indexer for Stellar that enables custom API creation for dapps and smart contracts with clean, indexed data. It supports indexing ledgers, transactions, operations, and effects from Stellar, as well as transactions and events from Soroban into a Postgres database.
 
-### [ZettaBlock](https://zettablock.com/)
-
-ZettaBlock offers real-time enterprise-grade data indexing infrastructure services to blockchain ecosystems through customizable, low latency APIs.
-
 ### [The Graph](https://thegraph.com/)
 
 A decentralized indexing protocol for querying blockchain data. The Graph allows developers to build and publish open APIs, called subgraphs, that make on-chain data easily accessible and searchable for their applications.