plots: small refactorings (#9206)

dvc/render/converter/vega.py

@@ -245,7 +245,7 @@ class VegaConverter(Converter):
         for i, (y_file, y_field) in enumerate(ys):
             if num_xs > 1:
                 x_file, x_field = xs[i]
-            datapoints = [d.copy() for d in file2datapoints.get(y_file, [])]
+            datapoints = [{**d} for d in file2datapoints.get(y_file, [])]
 
             if props_update.get("y", None) == "dvc_inferred_y_value":
                 _update_from_field(

dvc/repo/plots/__init__.py

@@ -157,9 +157,7 @@ class Plots:
         props: Optional[Dict] = None,
         onerror: Optional[Callable] = None,
     ):
-        from dvc.fs.dvc import DVCFileSystem
-
-        fs = DVCFileSystem(repo=self.repo)
+        fs = self.repo.dvcfs
 
         props = props or {}
 
@@ -506,10 +504,7 @@ def _collect_definitions(
     result: Dict = defaultdict(dict)
     props = props or {}
 
-    from dvc.fs.dvc import DVCFileSystem
-
-    fs = DVCFileSystem(repo=repo)
-
+    fs = repo.dvcfs
     dpath.merge(
         result,
         _collect_pipeline_files(repo, targets, props, onerror=onerror),