`plt.ioff()` not preventing automatic figure generation in jupyter

Using `plt.interactive(False)` or `plt.ioff()` in Jupyter (Lab and classic notebook) does not seem to prevent automatic figure generation, unless the magic `%matplotlib inline` in run first, even though the `inline` backend is the default.

### Example

```python
import matplotlib.pyplot as plt

plt.ioff()

fig, ax = plt.subplots()
a = 0
```

The figure still appears automatically under the cell.

### Note that

Explicitly running `%matplotlib inline` blocks figure creation (even though inline is the default activated backend in Jupyter):

Originally posted in https://github.com/matplotlib/matplotlib/issues/23766