[desktop] don't let user select a certificate if there is only one option

Description

this ticket is to answer a community bug: https://github.com/mattermost/desktop/issues/1328

if there is only one certificate for authentication, we shouldn't show the modal to choose as there is only one option, which makes the process quicker and less confusing. It also prevents any timeout from the OS or electron (which might be causing the above problem)

QA Test Steps

already discussed with jelena

Done
Your pinned fields
Click on the next to a field label to start pinning.

Mana

2

Assignee

Guillermo Vayá

QA Assignee

Jelena Gilliam

Reporter

Guillermo Vayá

Fix versions

Mattermost Team

Web Platform [Messaging]

Labels

QA Testing Areas

AD/LDAP

Components