Password manager prompt for ProtonMail encrypted mail

[Reactive12]

Description

When a password is entered for a ProtonMail (https://protonmail.com/) encrypted message, Brave's password manager prompts to update the ProtonMail account password.

Steps to Reproduce

1. "Compose" new message.
2. Select "Encryption" (Encrypt for non-ProtonMail users).
3. Enter password, confirm and "Set".
4. Brave password manager prompt may take several seconds to appear, requesting if the user would like to update their stored ProtonMail account password with the password that was set on the message.

Actual result:

Brave password manager prompt appearing to update the account password.

Expected result:

No prompt to update the account password.

Reproduces how often:

Easily reproduced.

Brave version (brave://version info)

Version 1.2.43 Chromium: 79.0.3945.130 (Official Build) (64-bit)

Version/Channel Information:

• Can you reproduce this issue with the current release? Yes.
• Can you reproduce this issue with the beta channel? Untested.
• Can you reproduce this issue with the dev channel? Untested.
• Can you reproduce this issue with the nightly channel? Untested.

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? No.
• Does the issue resolve itself when disabling Brave Rewards? No.
• Is the issue reproducible on the latest version of Chrome? Yes (tested in VirtualBox 6.1 and Linux Mint Cinnamon 19.2).

Miscellaneous Information:

• Linux Mint Cinnamon 19.1
• "Brave keyring" in use