[Bug]: pyplot.quiverkey does not work as expected with polar subplots

Bug summary

pyplot.quiverkey does not work correctly in polar plots.

Code for reproduction

import numpy as np
from matplotlib import pyplot as plt

fig, ax = plt.subplots(subplot_kw={"polar": True})

longitude = np.arange(0, 360, 10)
colatitude = 90 - np.ones_like(longitude) * 60

sample_x = np.ones_like(longitude)       # Northward
sample_y = np.zeros_like(longitude)      # Eastward

q = ax.quiver(np.radians(longitude), colatitude, sample_y, -sample_x, angles="xy")
ax.quiverkey(q, X=0, Y=0, U=5, label='5 units')

Actual outcome

Expected outcome

The quiverkey should be a single line rather than a cartwheel.

Additional information

No response

Operating system

macOS Ventura 13.5

Matplotlib Version

3.7.1

Matplotlib Backend

Installed osx event loop hook. MacOSX

Python version

3.10.11

Jupyter version

4.0.1

Installation

conda

首先，使用極座標 subplot 執行提供的 Python reproduction，並檢查 pyplot.quiverkey 的路徑及相關的 quiver-key 處理。將極座標結果與非極座標圖進行比較；完成的標準是極座標 quiver key 渲染為一條線而不是一個輪子，同時保留預期的 5 單位標籤。