Arabic text with less than 3 characters is not displayed

### Bug description

Arabic text is correctly displayed when the number of characters is equal or more than 3. But with 1 or 2 characters nothing is displayed.

For example:
```python

word = Text("صفي", font_size=96, font="Arial") # displayed
word = Text("في", font_size=96, font="Arial") # not displayed /!\
```

**Code**:

Following code display nothing
```python
class TextTransformExample(Scene):
def construct(self):
word = Text("في", font_size=96, font="Arial")

self.play(Write(word))
self.wait()
```

I tried changing the font, but it seems that the problem is not related to the font