Fix bug in +.ggplot()

[teunbrand]

Description

Hi there,

Apologies for not adhering to your checklist.
We've been preparing a new major release for ggplot2 and found an issue during a reverse dependency check.
We found some cases where +.ggplot was invoked and one of the components was a theme, and this would incorrectly be forwarded to patchwork::wrap_plot(). This PR fixes that issue.

In addition, there were some other issues I couldn't quite place, so I recommend checking against the development version of ggplot2 yourself too.
You can test your code with the development version of ggplot2 by installing it as follows:

# install.packages("pak")
pak::pak("tidyverse/ggplot2")

We aim to release the new ggplot2 version in about 2 weeks, and hope you can submit a fix to CRAN around that time or let us know when ggplot2 should change. Hopefully this will inform you in a timely manner.

Best wishes,
Teun

Checklist:

• PR form
  • Description above itemizes changes under subtitles, e.g. "## Data""
  • Any closed, fixed, or related issues are referenced and explained in the description above, e.g. "Fixed #0 by adding A"
  • Package builds on my OS without issues
• PR checks all pass for latest commit
  • CodeFactor check: Package improves or maintains good style
  • Package builds on Mac
  • Package builds on Windows
  • Package builds on Linux
  • CodeCov check: Package improves or maintains good test coverage
• Documentation
  • Any new or modified functions or data have roxygen style documentation in their .R scripts
  • Longer functions are commented inline or broken down into helper functions so that it is easier to debug in the future
  • PR description above and the NEWS.md file are aligned
  • DESCRIPTION file version is bumped by the appropriate increment (major, minor, patch)