Improve user experience when accepting an Invitation from an Email alias

Problem Definition

Sometimes users receive an invitation at an email address that is a confirmed Email alias in their Bitbucket account.
Since for authentication in Bitbucket only the primary email is used (linked Atlassian account email), if the user tries to accept this invitation, then:

• If an Atlassian account exists for this alias, they are prompted to log in to that Atlassian account and create a new Bitbucket account
• If no Atlassian account exists, they are prompted to create an Atlassian account and Bitbucket account with this email

This experience is sometimes confusing for users, especially if they are not aware that only the primary email can be used for authentication.
Users sometimes end up making duplicate accounts they may not need/want.

Suggested Solution

When a user accepts an invitation sent to an Email alias of their account, show a message when they accept this invitation:

1. informing them that the invitation should be sent to the primary email of their account instead
2. also add in the message that alternatively, they can create a new Bitbucket account with the email alias