Align LaTeX environment in matplotlib

In [162]: import matplotlib as mpl
In [164]: mpl.matplotlib_fname()
Out[164]: 'C:\\Users\\fubar\\anaconda3\\lib\\site-packages\\matplotlib\\mpl-data\\matplotlibrc'

## ***************************************************************************
## * LaTeX                                                                   *
## ***************************************************************************
## For more information on LaTex properties, see
## https://matplotlib.org/tutorials/text/usetex.html
#text.usetex: False  # use latex for all text handling. The following fonts
                     # are supported through the usual rc parameter settings:
                     # new century schoolbook, bookman, times, palatino,
                     # zapf chancery, charter, serif, sans-serif, helvetica,
                     # avant garde, courier, monospace, computer modern roman,
                     # computer modern sans serif, computer modern typewriter
                     # If another font is desired which can loaded using the
                     # LaTeX \usepackage command, please inquire at the
                     # matplotlib mailing list
#text.latex.preamble:   # IMPROPER USE OF THIS FEATURE WILL LEAD TO LATEX FAILURES
                        # AND IS THEREFORE UNSUPPORTED. PLEASE DO NOT ASK FOR HELP
                        # IF THIS FEATURE DOES NOT DO WHAT YOU EXPECT IT TO.
                        # text.latex.preamble is a single line of LaTeX code that
                        # will be passed on to the LaTeX system. It may contain
                        # any code that is valid for the LaTeX "preamble", i.e.
                        # between the "\documentclass" and "\begin{document}"
                        # statements.
                        # Note that it has to be put on a single line, which may
                        # become quite long.
                        # The following packages are always loaded with usetex, so
                        # beware of package collisions: color, geometry, graphicx,
                        # type1cm, textcomp.
                        # Adobe Postscript (PSSNFS) font packages may also be
                        # loaded, depending on your font settings.

import matplotlib as mpl
custom_preamble = {
    "text.usetex": True,
    "text.latex.preamble": r"\usepackage{amsmath}", # for the align enivironment
    }

mpl.rcParams.update(custom_preamble)

fig, ax = plt.subplots()
ax.set_label('x')
ax.set_ylabel('y')

ax.text(0.2, 0.9, r'eqnarray environment')
ax.text(0.2, 0.8, r"\begin{eqnarray*}f(x) &=  \sin x \\ &= \sin^2 (x) \end{eqnarray*}", transform= ax.transAxes)

ax.text(0.2, 0.3, r'align environment')
ax.text(0.2, 0.2, r"\begin{align}f(x) &=  \sin x \\ &= \sin^2 (x) \end{align}", transform= ax.transAxes)

ax.text(0.3, 0.6, r'array environment')
ax.text(0.3, 0.5, r"$$ |x| = \left\{ \begin{array}{rl} -x & \text{if } x < 0,\\ 0 & \text{if } x = 0,\\ x & \text{if } x > 0. \end{array} \right. $$", transform= ax.transAxes)