Fix mutable default in find_all_entries()

[Angeluz-07]

By reproducing the error that cause summary endpoint failing, with the tool locust in local . I caught the following exception returned from cosmos:

the sql query text exceeded the maximum limit of 262144 characters

This looked suspicious as only happened when the server was under big load. By adding some logs, I found the following section of query string growing on each call, e.g. :
First call

...
AND 
            ((c.start_date BETWEEN @start_date AND @end_date) OR
             (c.end_date BETWEEN @start_date AND @end_date))
...

Second call

...
AND 
            ((c.start_date BETWEEN @start_date AND @end_date) OR
             (c.end_date BETWEEN @start_date AND @end_date))
             AND 
            ((c.start_date BETWEEN @start_date AND @end_date) OR
             (c.end_date BETWEEN @start_date AND @end_date))
...

And so on. Until the query string become so big that exceeds the limit of character.

Later, I debugged the code and found the following piece of code, that was the cause that query string was growing on each call:

def find_all_entries(
        self,
        event_context: EventContext,
        conditions: dict = {},
        custom_sql_conditions: List[str] = [],
        date_range: dict = {},
    ):

where the list custom_sql_conditions was preserved across calls and It was not an empty list as expected. This is a classical error of mutable defaults in python as stated here

After fix this. I reproduced the error with about 15000 request and didn't fail for the former error. It had some fails because of azure blocking too much requests.

TODO :

• Fix this issue as a hotfix and make PR
• Create new issue to fix this classical error and avoid unexpected behaviors in the future because of this.