fix: minor plug-in and extension errors from logs

[frenchwr]

This cleans up a handful of minor issues I've noticed from the logs while running GIMP in verbose mode:

• Set locale directory for GIMP as plug-ins are failing to find this at runtime
• Set lua environment vars so the lua goat exercise extension works correctly (previously it was crashing)
• Update paths in GIMP's python interpreters file. Previously at startup GIMP was complaining that the previous paths were invalid (which they were), although Python plug-ins continued to work normally. I went ahead and fixed the interpreters file to use python3 from the core24 snap at /usr/bin/python3 as this is the interpreter shown from running which python3 while shelled into the snap, and GIMP no longer complains about the paths being invalid.

A few side notes:

• The preview branch would also benefit from these changes. The OpenVINO plugins were updated upstream last week to support GIMP 3.0-RC2 which means we should be able to merge the 2.99-openvino branch back into preview sooner than I expected. I hope to test in the next few weeks.
• Last week I published arm64 builds of openvino-toolkit-2404 and openvino-ai-plugins-gimp. I haven't tested them thoroughly but at least they are now available for those on arm machines wishing to test the plugins.

[brunvonlope]

We do not recommend enabling Lua: https://gitlab.gnome.org/GNOME/gimp/-/commit/78665ca3723f723ac313fdaeef5b62d41ab6b48d

It always crashes silently (despite the goat exercise working) and produces a loop when closing GIMP.

[frenchwr]

We do not recommend enabling Lua: https://gitlab.gnome.org/GNOME/gimp/-/commit/78665ca3723f723ac313fdaeef5b62d41ab6b48d

It always crashes silently (despite the goat exercise working) and produces a loop when closing GIMP.

Thanks for the heads up!

I commented the LUA_PATH and LUA_CPATH lines (and left a link to the upstream commit) for posterity so others don't try blindly enabling it like I did.

[jnsgruk]

Nice work, thanks. Look out for the Call For Testing post in a while!

[jnsgruk]

(I'll merge when the CI checks pass)