Create a file `credentials_searches.py` that contains a function `credentials_search` which takes no parameters and searches for the keys `password` and `secret` in a file called `logs.json`.
- If both keys are found, the function should create a new json file named 'credentials.json' and save the values of those keys in it.
- If only one of the keys is found, the function should create a new json file named 'credentials.json' and save the value of that key in it.
- If neither key is found, the function should not create the 'credentials.json' file.
- If the 'logs.json' file is empty or is not a json file, the function should not create the 'credentials.json' file.