Interactive matplotlib plots

[seeM]

We should support matplotlib's interactive mode i.e. ipympl.

For example, this should produce an interactive plot:

%matplotlib ipympl
import matplotlib.pyplot as plt
import numpy as np

fig, ax = plt.subplots()


x = np.linspace(0, 2*np.pi, 100)
y = np.sin(3*x)
ax.plot(x, y)

Currently it produces a static low-res plot:

Sub-issue of https://github.com/posit-dev/positron/issues/1924.