Ensure gg_season() breaks are not out-of-bounds

[teunbrand]

Hi Mitchell,

For completion, I'll repeat that we've been preparing a new release of ggplot2 and during a reverse dependency check, it became apparent that the prospective ggplot2 3.5.0 would break feasts.

This PR updates a break calculation in gg_seasion(). Briefly, when breaks = waiver(), the automatic break calculation can include 0. In the labels function, subsetting using 0 gives an empty vector, which caused a mismatch between length(breaks) and length(labels).

To test the code changes with the release candidate, you can install it with the code below:

remotes::install_github("tidyverse/ggplot2", ref = remotes::github_pull("5592"))

The release of ggplot2 3.5.0 is scheduled for the 12th of February. The progress of the release can be tracked in tidyverse/ggplot2#5588. We hope that this PR might help feasts get out a fix if necessary.

[teunbrand]

This is just a kind reminder that the release is scheduled soon.

[mitchelloharawild]

Thanks! I'll prepare a release as soon as possible.