Default toolbar overlaps figure

Nessuno ha ancora preso questa issue.

## Describe the issue
The default position of the toolbar is on the left, where it overlaps the figure.
Especially when the `constrained_layout=True` keyword is used when creating the figure,
this is highly undesirable.

Possible solutions or workarounds:
- Minimal fix: Change the default to anything other then "left"; I think that with the current design, "right" would be by far the best. It would minimize the likelihood of an overlap.
- The real fix: When the toolbar_position is on the left, position the figure to its right. Ideally, all toolbar positions should be in boxes that never overlap the figure box. With this scheme I suggest putting the default toolbar on the top or bottom, and flush left, to match all of the other matplotlib interactive backends.

## Versions

```
3.8.13 | packaged by conda-forge | (default, Mar 25 2022, 06:06:49)
[Clang 12.0.1 ]
ipympl version: 0.9.2
Selected Jupyter core packages...
IPython : 8.5.0
ipykernel : 6.16.0
ipywidgets : 7.7.0
jupyter_client : 7.3.5
jupyter_core : 4.11.1
jupyter_server : 1.23.1
jupyterlab : 3.5.0
nbclient : 0.6.8
nbconvert : 7.0.0
nbformat : 5.6.1
notebook : 6.5.2
qtconsole : 5.3.1
traitlets : 5.4.0
Known nbextensions:
config dir: /Users/efiring/.jupyter/nbconfig
notebook section
matplotlib/extension enabled
- Validating: problems found:
- require? X matplotlib/extension
config dir: /Users/efiring/miniconda3/envs/py38/etc/jupyter/nbconfig
notebook section
jupyter-matplotlib/extension enabled
- Validating: OK
jupyter-js-widgets/extension enabled
- Validating: OK
JupyterLab v3.5.0
/Users/efiring/miniconda3/envs/py38/share/jupyter/labextensions
jupyterlab_pygments v0.2.2 enabled OK (python, jupyterlab_pygments)
jupyter-matplotlib v0.11.2 enabled OK
@jupyter-widgets/jupyterlab-manager v3.1.1 enabled OK (python, jupyterlab_widgets)

```

The issue centers on the toolbar_position behavior in the Jupyter Notebook integration; start by locating the implementation that places the default toolbar and any related layout tests. Reproduce the overlap with constrained_layout=True, then verify that the toolbar and figure occupy separate boxes for the chosen positioning behavior.

Scritto dal modello di indicizzazione a partire dal testo della issue.