[Bug]: Axes.cla() with sharex may wrongly reset the axes limit.

Bug summary

For example, when subplot A shares the x-axis with subplot B (A is created with sharex=B), a call to B.cla() will set the xlimit to [0, 1], which may not be expected (in contrast, a call to A.cla() will not change the xlimit).

I think the main problem comes from the following function, where it will check whether its _sharex attribute is None; however, in this case, B is shared to A, but no axis is shared to B, so B's _sharex attribute is None.
https://github.com/matplotlib/matplotlib/blob/9e18a343fb58a2978a8e27df03190ed21c61c343/lib/matplotlib/axes/_base.py#L1369

Code for reproduction

ax = plt.subplot(211)
ax2 = plt.subplot(212, sharex=ax)
ax.plot(range(50))
ax2.plot(range(50))
ax.cla()
plt.show()

Actual outcome

Expected outcome

Additional information

No response

Operating system

No response

Matplotlib Version

3.8.3

Matplotlib Backend

'TkAgg'

Python version

3.9.13

Jupyter version

No response

Installation

pip

阅读 lib/matplotlib/axes/_base.py 中链接的 Axes.cla() 代码，然后运行提供的、使用 sharex 的 subplot 复现。跟踪当 B 与 A 共享坐标轴时，共享坐标轴关系是如何表示的，并在不重置 x-limit 的情况下使行为符合预期结果。确认该复现不再意外更改 limit。