First of all, best of luck for your interview. I hope you do well and get the job.
For a senior QA to transition into a QA Manager role can be a challenging task and at the same time if you have good skills, you can transition seamlessly.
One of the important aspects that QA Manager has to do is to have good conflict resolution skills and the ability to make a decision based on the need of the project.
I say this so, because as a QA Manager, there would be many times when you might have to act as a judge between conflicts- that can be within people who report you directly or between two people, who are on different teams, one of which would be led by you.
I have seen instances where the QA Manager or the QA Lead, is expected to take the side of QA people, since , you are from a QA/Testing background, and these are the times when you would be to have the best skills to resolute a conflict, with the best interest of both the project, company and people.
Another skill that you should have or rather that you would need to learn quickly is the effective delegation of work to your team.