feat(Proton Mail): Change free accounts limit

[ByteEVM]

Feature description

Proton Mail (mobile) restricts the number of free accounts (emails) you may have logged in. This restriction currently sits at 2 accounts.

Other email providers such as Gmail allow their users to manage more accounts "concurrently" (without having to log out, by simply switching them).

The goal is reassigning this limit to a higher default (such as 10) — and up to customization with a patch option.

_{P. S. I have already implemented this feature (first one), this issue is merely "informative", as I'm not sure if releasing the patch could result in any undesired "implications".}

Motivation

Managing multiple emails shouldn't be a hassle.

For users with <= 2 emails within Proton (e.g. just personal and work), this might not be a valid motivation.

Acknowledgements

• I have checked all open and closed feature requests and this is not a duplicate
• I have chosen an appropriate title.
• All requested information has been provided properly.