Adjust to MetaCursor changes in GNOME 48

[DaPigGuy]

Description

Adjusted usage of MetaCursor enum for changes that were merged last minute in GNOME 48. Additionally, cleaned up GNOME shell version compatability methods to make this change easier.

upstream gnome PR ref: https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3622

Fixes #350

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist

• My code follows the style guidelines of this project
• My commits follow the commit standards of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have checked my code and corrected any misspellings

[Totto16]

Thanks for this, as even the unofficial docs of Meta don't have this (https://gjs-docs.gnome.org/meta16~16/meta.cursor) , but the PR that added this into gnome 48 was really late xD

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3622

[Totto16]

I changed a few minor things in both commits:

In the first, make the retrieval of the gnome version safer, don't use map, but reduce, so that non-numbers get removed from the final array. Upstream guarantees, that this string is a valid version number, but we newer know, so there are explicit error messages, that are printed, when this unlikely scenario happens

In the second commit, I uses javascript checks instead of gnome version checks, as this is preferred, if we have the option, the gnome version check is only done in 1 place, where we need to, in all other places w check for features, even if we know the version it was introduced. This is due to the fact, that that is much more robust and support all versions, even gnome-48 beta before this change.

Feel free to suggest changes, if you are not happy with mine :)

[DaPigGuy]

Feel free to merge