Handle project not found situations for mining scripts

[penyuan]

During the GitHub Actions run of the mining script today, it failed with:

Processing: https://wikifactory.com/+elektrictube/pikon-telescope
Retrieving +elektrictube/pikon-telescope's data...

...

  File "osmine/miner/Wikifactory.py", line 550, in Wikifactory
    response_data: dict = get_project_data(repo_url=repo_url)
  File "osmine/miner/Wikifactory.py", line 366, in get_project_data
    if response["license"] is None: 
TypeError: 'NoneType' object is not subscriptable

I checked and turns out https://wikifactory.com/+elektrictube/pikon-telescope is not at https://wikifactory.com/+elektricworks/pikon-telescope (they changed their name?). So I think the Wikifactory API is returning some sort of "project not found" error leading to the error above.

I suspect this can be solved more comprehensively by making the mining scripts handle situations where not only invalid repository URLs but also URLs leading to repository not found.