Remove BATCH_UPDATE_DOWNLOADS feature flag (#8200)

We've very successfully used this on production for almost two weeks now. There does not appear to be any reason for switching it back off, so this commit is removing the feature flag and permanently enables the batch processing.

Author: Turbo87

src/config/server.rs

@@ -45,9 +45,6 @@ pub struct Server {
     pub cdn_log_counting_enabled: bool,
     pub cdn_log_storage: CdnLogStorageConfig,
     pub cdn_log_queue: CdnLogQueueConfig,
-    /// If `true`, the `update_downloads` background job will use batch
-    /// processing with a static SQL query.
-    pub batch_update_downloads: bool,
     pub session_key: cookie::Key,
     pub gh_client_id: ClientId,
     pub gh_client_secret: ClientSecret,
@@ -189,7 +186,6 @@ impl Server {
             cdn_log_counting_enabled: var("CDN_LOG_COUNTING_ENABLED")?.is_some(),
             cdn_log_storage: CdnLogStorageConfig::from_env()?,
             cdn_log_queue: CdnLogQueueConfig::from_env()?,
-            batch_update_downloads: var("BATCH_UPDATE_DOWNLOADS")?.is_some(),
             base,
             ip,
             port,

src/tests/util/test_app.rs

@@ -431,7 +431,6 @@ fn simple_config() -> config::Server {
         cdn_log_counting_enabled: false,
         cdn_log_queue: CdnLogQueueConfig::Mock,
         cdn_log_storage: CdnLogStorageConfig::memory(),
-        batch_update_downloads: true,
         session_key: cookie::Key::derive_from("test this has to be over 32 bytes long".as_bytes()),
         gh_client_id: ClientId::new(dotenvy::var("GH_CLIENT_ID").unwrap_or_default()),
         gh_client_secret: ClientSecret::new(dotenvy::var("GH_CLIENT_SECRET").unwrap_or_default()),