Always fetch transaction status via waitForConfirmation in browser

[smonn]

Overview

Today when the client need to wait for a transaction to be confirmed we setup a unique endpoint to poll the status we record in our database, which in turn we get by also polling an Algod node. Instead, I suggest the client always polls a public Indexer (or public Algod node) to avoid hammering the API with status requests. This pattern is already being implemented for the export NFT flow, but could be added for the purchase flow and any other place we need to check/wait for the transaction status.