Optimize generated gifs.

src/holt59/aoc/utils/api/files.py

@@ -14,3 +14,4 @@ class FileHandlerAPI(FileHandler):
         with open(self.folder.joinpath(filename), "wb") as fp:
             fp.write(content)
         dump_api_message("file", {"filename": filename, "size": len(content)})
+        return self.folder.joinpath(filename)

src/holt59/aoc/utils/files.py

@@ -18,3 +18,4 @@ class SimpleFileHandler(FileHandler):
             self.folder.mkdir(exist_ok=True)
             with open(self.folder.joinpath(filename), "wb") as fp:
                 fp.write(content)
+            return self.folder.joinpath(filename)