Add support for choosing actual default profile, not the one named *default*

[txtsd]

Many people use a different profile as their default firefox profile, and it doesn't necessarily contain the word default in its directory name.

Add support to find the actual default profile and use the cookies from there.

[sefeng211]

Just a note for a hack if you are struggling with finding the correct profile to log in.

It's all rely on browser_cookie3 to find the cookie, and by executing browser_cookie3.Firefox.find_cookie_file() in the python interpreter, one can find which profile has been used for browser_cookie3. Then you can log in to leetcode by using that profile.