Bug summary

When I do once of setting xlabel of ylabel to left of right, it cannot reset label of axis to center any way.

Code for reproduction

if I do once:
ax.set_xlabel("my label",loc="left ") 
or:
ax.set_xlabel("my label",loc="right")
the following will have no any effect:
ax.set_xlabel("my label",loc="center")

Actual outcome

No any output

Expected outcome

reset the label to center

Additional information

No response

Operating system

win 10 x64

Matplotlib Version

3.4.3 and 3.5

Matplotlib Backend

Qt5, Qt6,

Python version

3.9, 3,10

Jupyter version

No response

Installation

pip