Hi Filbert.
Generally, what you have written is correct: Once Pulse's credential provider is enabled, the end user is not given a choice of whether to log into the desktop with the Pulse credential provider tile or a non-Pulse tile. The Pulse tile is generally the only option.
That said, the end user can always log in with the Pulse tile, then when the VPN connection is being established, the end user can hit the "Cancel" button to terminate the VPN connection attempt, but then continue to log into the desktop.
If that's not an acceptable workaround, then I recommend that you reach out to the Pulse Secure Global Support Center or directly email
[email protected] (and reference this forum post) for guidance. There may be other options, but they are complicated and would need to be discussed with support personnel.