feat: Enable code suggestion for project that are not hosted on GitLab

Description

This MR implements two changes that are correlated with each other:

1. It removes restriction of active project being present from Code Suggestions feature to work. It would enable usage of code suggestions for project that are not hosted on GitLab instance as long as plugin is authorised to account that has Code Suggestions feature (main goal requested by https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/issues/836)
2. It replace a check if project is hosted on GitLab.com to enable new API with version based check.

2nd change wasn't a hard requirement to enable 1st but it vastly simplifies mental model of executions flows happening in Code Suggestions client

Verification

1. Run extension on local
2. Authenticate to account that has code suggestions enabled (possibly gitlab.com one)
3. Open any project and enjoy code suggestions