Update Sphinx and requirements

[Piralein]

supersede #7443

• Update CI OS version for sphinx 8.x support (I guess phyton version?)

• disable social cards, because of warnings

• remove html_theme_path and display_version as this are outdated options

• remove search css, as this shouldn't be required anymore

• remove cache busters, as this is now integrated

• remove pinned dependencies

• update dependencies

• class_scripteditor.rst: document is referenced in multiple toctrees: ['classes/index', 'classes/index'], selecting: classes/index <- classes/class_scripteditor is an information and can't be suppressed, like a warning. (as far as I know)

[mhilbrunner]

I've been testing this these past few days and had no issues, so I think we can go ahead with this, considering the current trouble with the outdated build we currently use. Both the web/HTML build and the EPUB one seem to work.

class_scripteditor.rst: document is referenced in multiple toctrees: ['classes/index', 'classes/index'], selecting: classes/index <- classes/class_scripteditor is an information and can't be suppressed, like a warning. (as far as I know)

The discussion on the Sphinx 8.1 release at first made me think this was just an error on the Sphinx side (see this issue: sphinx-doc/sphinx#13012). And to quote:

for now, the lines are safe to ignore -- they're informational only. We will see if there is something we can do to improve the experience

However, it felt a bit odd that this only happens to a very limited set of files in the class reference: Editor-only classes, and Node/Resource/Object.

It seems they are the classes that are listed more than once in the class reference index (classes/index.rst, autogenerated by make_rst.py in the main engine repo).

For example, class_editorcommandpalette is listed once in the general Nodes toctree in that file, and a second time in the Editor-only toctree. For now, this only seems to result in a a warning; both generated links in the sidebar appear to work. However, we may need to think about fixing this behaviour in the future.

I guess for social cards, you mean these warnings?

WARNING: [Social card] image cannot be an SVG image, skipping...

[Piralein]

I guess for social cards, you mean these warnings?

WARNING: [Social card] image cannot be an SVG image, skipping...

Yes, I haven't checked if this is still an issue. I added it at the time and never removed it as we probably don't want them anyway.

[mhilbrunner]

It definitely is still an issue. Not sure if wanted or not, I think social cards were at least nice once upon a time for Twitter, but with how that whole thing is going, well. Alright, not that much of a priority anyway, let's go ahead and merge this and see how it pans out for everyone on master/latest at least. Thanks for your work :)

[mhilbrunner]

Cherrypicked to 4.3 in #10346.