fix homepage advertisement z-index

sometimes when an advertisement is long enough, it covers up the buttons on the profile dropdown and they are both unviewable and unclickable (see screenshot)

<img width="320" height="256" alt="Image" src="https://github.com/user-attachments/assets/b16bd3a7-0ae8-4542-9023-c5d2e731b319" />

we need to change the z index of the profile dropdown to make sure it comes above the advertisement 