AI Assistant settings suggested by form placeholders require additional modules

Test failures related to composer PHP versions not the changes introduced here, so I'll leave this to be reviewed.

Note: the MR changes the AIAssistantForm from being a final class to being a standard class. I don't think this will be a major issue, as I can't see any obvious reason why the form shouldn't be extended.

Test issues resolved upstream.

Some minor comments on the MR: https://git.drupalcode.org/project/ai/-/merge_requests/184. You can check them, but nothing stopping a merge.

I will check so the feature itself is approved by the others, but I think its a good feature since the AI Assistants API is hard to setup and recipes will not be context aware enough (I think, I could verify that with mandclu or someone else from the recipe team).

Really like this! Could I get some screenshots of what this might looks like?

Do you imagine the tempting system to be a page within Drupal for end users? Or something in code? Like example yaml files?

@yautja_cetanu - the code is already done from Paul :) You can see one example here: https://git.drupalcode.org/project/ai/-/blob/44f5fd3177a60fb530c39e83df8... (I have already asked for some changes to it)

@yautja_cetanu Some screenshots for you.

@Marcus_Johansson With regards implementing a plugin system for this, it feels like overkill to me: a plugin system to gather settings to store in a config entity that users can conditionally create feels like a lot of steps. But thinking that has made me wonder if I've over-engineered the whole thing here: couldn't we just use Drupal's existing methods for modules to provide config on install to create partial, unpublished AI Assistants? If the user wanted to use them, they could edit, complete and publish them, and if they didn't they could delete them.

I will close this, since we are moving over to using agents as the assistants in 2.0.0 and its already introduced in 1.1.0.