wl-paste cannot paste screenshot from Phosh
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### Describe your issue
#### What's the expected behaviour?
`wl-paste` (from [wl-clipboard](https://github.com/bugaevc/wl-clipboard)) should be able to paste the screenshot that Phosh copies to the clipboard.
#### What's the current behaviour?
`wl-paste` hangs indefinitely after taking a screenshot in Phosh.
#### How to reproduce your issue?
Take a screenshot in phosh, by long-pressing the physical power button to open the power menu and then touching the "screenshot" button that appears.
A notification states that a screenshot has been copied to the clipboard, and running `wl-paste --list-formats` indicates that an image is on the clipboard. However, running `wl-paste > new-screenshot.png` hangs indefinitely.
I also seem unable to paste the screenshot into Firefox. Copying images out of Firefox and pasting with wl-paste works.
### What device are you using?
oneplus-enchilada
### On what postmarketOS version did you encounter the issue?
* [x] edge (`master` branch)
* [ ] `v23.06`
* [ ] `v22.12` (Supported until 2023-07-06)
* [x] I confirm that the issue still is present after running `sudo apk upgrade -a`
### On what environment did you encounter the issue?
#### Environments
* [ ] GNOME Shell on Mobile
* [x] Phosh
* [ ] Plasma Mobile
* [ ] Sxmo (Wayland/Sway) **Please post the output of `sxmo_version.sh`**
* [ ] Other: **Please fill out**
### How did you get postmarketOS image?
* [x] from https://images.postmarketos.org
* [ ] I built it using pmbootstrap
* [ ] It was preinstalled on my device
### What's the build date of the image? (in yyyy-mm-dd format)
unsure
### Additional information
Logs and more info may be found at [this upstream bug report](https://gitlab.gnome.org/World/Phosh/phosh/-/issues/971) which I filed before learning that this seems to be due to the version of GTK3 that PmOS ships.
It appears that this is fixed with a newer GTK3 version (3.24.37, from March 2023). It appears that the PmOS GTK3 package is two years old, and ships [this commit](https://source.puri.sm/Librem5/debs/gtk/-/commit/f05e4021ed82bfbabf566398d0511b6745a5745e). Probably we should ship a more recent actual release from the librem5 repo, but not a [random MR commit](https://gitlab.postmarketos.org/postmarketos/pmaports/-/commit/e405a87b77a794605cf0a6ef36fd72f6806bbe63) from 2 years ago.
issue