feat(downloads): Convert DownloadThreadControlFlag to AtomicBool

Also ran cargo fmt & cargo clipy

Signed-off-by: quexeky <git@quexeky.dev>

src-tauri/src/downloads/mod.rs

@@ -1,4 +1,4 @@
 pub mod download_agent;
 pub mod download_commands;
 mod download_logic;
-mod manifest;
+mod manifest;