TF-3456 Checkbox to be able to accept self-signed certificates

[florentos17]

tackling issue #3456

the design can easily be changed, for now i kept it simple with an ExpansionTile and a LabeledCheckbox

here is a video demo:

demo-checkbox-accept-ssc.webm

[florentos17]

I noticed a flaw in my previous work: with the current state, self-signed certificates can be accepted upon login (cf demo) but the choice is not remembered for later requests.
For example, if the users checks accept, he can login to a server using a self-signed certificate, but later when he wants to upload an attachment for an email, an Bad Handshake error is thrown.

Here is what happens:

1. When the app starts, Get.put() registers a DioClient with default settings, meaning self-signed certificates are rejected ;
2. When the user logs in, OIDCHttpClient updates its own DioClient instance to accept or reject self-signed certificates based on the user’s choice ;
3. Later, whenever a DioClient is needed, Get.find() retrieves the initially registered instance, which still has the default settings (self-signed certificates are not accepted).

Possible solutions:

• One solution would be to cache the user’s choice and change DioClient's constructor to apply the cached setting, if any.
• Or, maybe easier, once the user has made its choice, replace the existing DioClient in GetX with a new one that has the correct setting ? The problem with that is, GetX already registered many objects based on the initial DioClient (OIDCHttpClient, DownloadClient, EmailAPI...). It would be easier to just erase and reload every NetworkBindings dependency ? Would that be acceptable ?