refactor: Remove is_supported from LZ4 engine

src/compression_engine/lz4.rs

@@ -18,10 +18,6 @@ impl CompressionEngineLZ4 {
 }
 
 impl CompressionEngine for CompressionEngineLZ4 {
-    fn is_supported(&self) -> bool {
-        true
-    }
-
     fn open(&self, file_path: PathBuf) -> Result<Box<dyn Read>> {
         debug!("COMPRESSION: Opening {:?} using {:?}", file_path, *self);