[VS Code]: Clean up redundant policies for code suggestions

Problem

The CodeSuggestionsStateManager is now a strange class combining some legacy policies and also reflecting the new LanguageServerPolicy

Several of the state manager polices seem to be redundant/not used:

• minimum GitLab version
• license status
• project disabled in settings
• supported language

Solution

We should clear the unused polices, which will make transition to the ExtensionState as defined in gitlab-org/editor-extensions&82 much easier.