Justify axis agnostic of label presence

[teunbrand]

This PR aims to fix #6574.

Essentially in #5826 I was too careful, to only apply justification if the axis had labels.
Now the justification is applied regardless of whether a guide has labels or not.

Reprex from issue:

devtools::load_all("~/packages/ggplot2/")
#> ℹ Loading ggplot2

ggplot(mtcars, aes(disp, mpg)) +
  geom_point() +
  coord_radial(r.axis.inside = TRUE) +
  theme(axis.text.r = element_blank())

^{Created on 2025-09-05 with reprex v2.1.1}