Fix: NoneType error when adding new query

[jaco-99]

Issue

This PR addresses issue #38.
When attempting to add a new query in certain situations, the following error is raised: AttributeError: 'NoneType' object has no attribute 'get'.

The error can occur for two reasons:

1. Attempting to add a query that was previously added but with different parameters (e.g., without the --minPrice and --maxPrice arguments):

$ python3 subito-searcher.py --add RTX_2060_Super --url "https://www.subito.it/annunci-italia/vendita/elettronica/?q=super+2060" --minPrice 0 --maxPrice 110
2024-12-29, 17:45:40 running query ("RTX_2060_Super" - https://www.subito.it/annunci-italia/vendita/elettronica/?q=super+2060)...

2024-12-29, 17:45:45 New search added: RTX_2060_Super
2024-12-29, 17:45:45 Adding result: GTX 1060 6GB MSI OC EDITION Scheda Video - 100 - Santa Maria Capua Vetere (CE)
2024-12-29, 17:45:45 Query added.

$ python3 subito-searcher.py --add RTX_2060_Super --url "https://www.subito.it/annunci-italia/vendita/elettronica/?q=super+2060"
2024-12-29, 17:45:50 running query ("RTX_2060_Super" - https://www.subito.it/annunci-italia/vendita/elettronica/?q=super+2060)...
Traceback (most recent call last):
  File "/.../subito-it-searcher/subito-searcher.py", line 335, in <module>
    run_query(args.url, args.name, False, args.minPrice if args.minPrice is not None else "null", args.maxPrice if args.maxPrice is not None else "null",)
  File "/.../subito-it-searcher/subito-searcher.py", line 227, in run_query
    if not queries.get(name).get(url).get(minPrice).get(maxPrice).get(link):   # found a new element
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'get'

2. Adding a new query where the first product identified on the website has already been sold. This error seems to have been the issue encountered in PR Impossibile aggiungere prodotti da tracciare #38.
   The error occurs because the query being accessed in the dictionary had not yet been added. The problematic code is shown below:

# check if the product has already been sold
if sold != None:
    # if the product has previously been saved remove it from the file
    if queries.get(name).get(url).get(minPrice).get(maxPrice).get(link): # ON THIS LINE
        del queries[name][url][minPrice][maxPrice][link]
        products_deleted = True
    continue

Solution

This PR aim to resolve both issues by recreating the query every time the user uses the --add and --url arguments to add a new one, even if a query with the same name already exists. This ensures that updated parameters are correctly applied (1), and the query is properly initialized before accessing it (2).