## Issue
Double ads on screen
## Reproduce
- Pre re-design:
- Change "Only Language" from tne locale nag.
- Post re-design:
- Follow a bunch of channels with active livestreams. The homepage ad will show 2 ads stack on each other, with second one invisible.
Both should be equivalent, just different UI/style.
## Analysis
In both cases, it is due to `removeIfExists` failing to remove the element if the ad script hasn't run yet.
This can happen when the component is re-mounted immediately after the ad script was added. When the effect-cleanup runs, the script have not started or is running halfway.
Aside: The need to run `removeIfExists` further strengthens my hunch that the script is meant to live throughout the lifetime of the app, with it populating the given div as we navigate. But just my guess.
## Approach
Clean up before adding the script as well. This covers any missed elements from the previous cleanup.
The drawback is that this approach assumes there will only be 1 ad per page, but that's pretty much the case with the existing `removeIfExists` approach.
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