Contact email set by user is not cleared when switching accounts

[guarani]

Expected behavior

When logging into a new WP.com account, any contact email that the user set during previous sessions should be discarded.

Actual behavior

If I set a contact email and then log out and log into a new account, the old contact email is still set.

This bug is present on JPiOS and WPiOS (thanks @momo-ozawa for verifying this!)

Steps to reproduce the behavior

1. Tap the profile pic
2. In the support section, set a contact email
3. Log out and log in with a new account
4. Go to the support section and notice that the contact email is still set (it should be cleared)

Tested on iPhone 11, iOS 16, WPiOS 21.1