You are not impeding them or obstructing them from carrying out their duties - they have, evidently, been able to arrest the intended person and you did nothing to prevent them from doing so. Everything would have presumably occurred exactly as pictured whether or not you were filming (up until the point where you were challenged on filming, of course).

I am not a lawyer, but a woman approached the officer and the officer advises her not to speak due to it potentially being uploaded onto the internet.

The woman may have been the person who called the police and wanted to figure out how to proceed further. I don't know what specific law it would be, but I do know that the police do have a right to move you on in such instances as you are disrupting them. Whether or not that extends to seizing the phone itself, I don't know.