How do I unlink my phone number from my Turbo Tax account?

Today when I tried to E-file my taxes via Turbo Tax I was prompted to enter a phone number, which was described as a thing to add for convenience. I did not want to add one, but the user interface gave me no way to skip adding one. I wanted to file my taxes without delay, so I entered my phone number.

 

After filing my taxes I checked my intuit account and found that under "Sign-in and security" it now lists my phone number. I do not want any security benefits that may come from having a phone number linked to the account. I wish to make it impossible for my phone number to be used as a means of authenticating me with intuit, and I wish to make sure that it is impossible for intuit to attempt to contact me via voice or text message. In short, I want to unlink the phone number from my account and return it to the state it was in at the start of today: no phone number associated.

 

The user interface under "Sign-in and security" provides an option to change the phone number, but not an option to delete it altogether.