fix new clippy lints (#5160)

# Objective

- Nightly clippy lints should be fixed before they get stable and break CI
  
## Solution

- fix new clippy lints
- ignore `significant_drop_in_scrutinee` since it isn't relevant in our loop rust-lang/rust-clippy#8987
```rust
for line in io::stdin().lines() {
    ...
}
```

Co-authored-by: Jakob Hellermann <hellermann@sipgate.de>

src/loader.rs

@@ -1027,8 +1027,7 @@ async fn load_buffers(
                     Err(()) => {
                         // TODO: Remove this and add dep
                         let buffer_path = asset_path.parent().unwrap().join(uri);
-                        let buffer_bytes = load_context.read_asset_bytes(buffer_path).await?;
-                        buffer_bytes
+                        load_context.read_asset_bytes(buffer_path).await?
                     }
                 };
                 buffer_data.push(buffer_bytes);