v1.31.4

Plots v1.31.4

Diff since v1.31.3

Closed issues:

• [BUG] 4243 severely impacted contour subplots (#4273)
• [FR] limits of the r in the polar plot (#4281)

Merged pull requests:

• don't set unit vector by default for pgfplotsx backend (#4271) (@BeastyBlacksmith)
• keep largest size of subplots when plotting plots (#4275) (@BeastyBlacksmith)