Country borders out of scope for polar projections w/ axes=False

[sadielbartholomew]

When doing (at least) contour plotting with the projection set with mapset to either of the polar stereographic cases, "npstere" or "spstere", and axes=False set to turn off x and y axes plotting, the country borders go out-of-scope of the circular plotting area for the data appearing to be square with the same height/width as the circle diameter (see example images below), so ultimately they are unaligned with the data. Note this issue does not affect other projections (as tested), only these polar ones.

May be related to #55, which also concerns incorrect plot output with the polar stereographic projections, but doesn't look immediately similar in terms of user-facing/plot outcome issue.

MRE with environment

import cfplot as cfp
import cf

cf.environment()

f = cf.read(f"{PATH}/ggap.nc")[0]

cfp.gopen(file="mre-1.png")
cfp.mapset(proj="npstere")  # or set with "spstere" instead
cfp.con(
    f.subspace(pressure=850),
    axes=False,
)
cfp.gclose()

Outputs from MRE

With the axes=False line in, the issue occurs:

npstere

spstere

Working cases, for comparison

Whereas without axes=False, everything is OK: