DiGraph edges not being laid out properly

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## Description of bug / unexpected behavior

When I added a DiGraph the edges were 'crocked'. They were not aligned from center-to-center to each 'Node' (or vertex).


## Expected behavior

This should be the expected output (this oe i got drom modifying the Graph.


## How to reproduce the issue

The error code
```python
class Issue(Scene):
def construct(self):
vertices = [0, 1, 2, 3, 4, 5, 6, 7]
verticesGraph = [3, 1, 2, 0, 4, 7, 6, 5]
edges = [(0,2), (0,3), (0,4), (1,2), (1,7), (2,5), (3,5), (3,7), (4,7), (5,6), (6,7)]

adj_list = {v: [] for v in vertices}
for i, j in edges:
adj_list[i].append(j)

graph = DiGraph(verticesGraph, edges, layout='circular', layout_scale=2.7,
vertex_mobjects={v : Node(v) for v in vertices},
edge_config={"stroke_color": EDGE_COL, "stroke_width": 6})

self.add(graph)
```

This is the code i used for the 'Expected' output
```python
class DAGArrow(Arrow):
def __init__(
self,
*args: Any,
**kwargs: Any,
):
super().__init__(buff=0.46, *args, **kwargs)

class Issue(Scene):
def construct(self):
vertices = [0, 1, 2, 3, 4, 5, 6, 7]
verticesGraph = [3, 1, 2, 0, 4, 7, 6, 5]
edges = [(0,2), (0,3), (0,4), (1,2), (1,7), (2,5), (3,5), (3,7), (4,7), (5,6), (6,7)]

adj_list = {v: [] for v in vertices}
for i, j in edges:
adj_list[i].append(j)

graph = Graph(verticesGraph, edges, layout='circular', layout_scale=2.7,
vertex_mobjects={v : Node(v) for v in vertices},
edge_config={"stroke_color": EDGE_COL, "stroke_width": 6},
edge_type=DAGArrow)

self.add(graph)
```

Start by running the provided Python Scene reproduction with DiGraph and compare its edge construction with the Graph example using DAGArrow. Inspect the DiGraph, Graph, Arrow, and Node entry points involved in edge placement; done means directed edges align center-to-center with the vertices in the circular layout.

Written by the indexing model from the issue text.