Fetch projects if not in cache

[pumbas600]

Currently, if you do @[ProjectName] using a project not in the cache (I.e. any new projects) then it doesn't return any results.

This is because the filteredProjects list at this line https://github.com/JamesNZL/flow-toggl-plugin/blob/main/src/TogglTrack.cs#L933 is empty.

Currently, you can get around this by doing tgl refresh to clear the cache and then getting it to refetch everything.

Ideally, if the filteredProjects list is empty, then an API call will be made to see if there are any new projects. Some considerations I've not had time to dig into:

• How often is this function called? Ideally, this logic should only be run if the query has stabilised.
• The rate limit of the Toggl API. If it's fairly conservative, then potentially, it should only do this if you're not close to hitting the rate limit.