Support license validation with Exchange accounts

[RealRaven2000]

The default identity of an email configured via Exquilla is not visible to the license validation algorithm and will lead to the quickFilters Pro license not being validated when Thunderbird starts up:

However if one manually clicks validate on this key the validation works. This is caused by the accounts being loaded after quickFilters has already started up when the exchange account is added.

[RealRaven2000]

Here is a version that can validate an exchange (or any other 3rd party) account license. It will only work from Thunderbird 98 forward and newer, as the API accounts.onCreated has only been added in that version. It's currently not possible to check Exchange accounts in this way in Thunderbird 91.

quickFilters-wx-5.6pre27.zip

to install this version, download the zip file and drag it into Thunderbird Add-ons Manager. (Do not unpack the files)

[RealRaven2000]

To do: update visible tabs (some are still grayed out after restart!)

[RealRaven2000]

Implemented in 5.12, released on 16/08/2022