Tipping banner does not scale properly based on viewport size

[Miyayes]

Issue: Tipping banner does not scale properly based on viewport size. If viewport size is smaller than usual because of, e.g., docked dev tools, the tipping banner will appear shorter horizontally, and users will have to scroll side to side inside it to use it.

Even when the developer tools are later closed, the tipping banner does not scale back to proper size, but remains horizontally short.

UX symptom: Users cannot click outside the banner to close it, but instead need to press the X button. But the X button is outside view, so users have to know to scroll sideways to get to it.

Reproduce:

1. Open a website you'd like to tip
2. Open dev tools (docked on right side)
3. Open tipping banner

[NejcZdovc]

closing as dupe of #1658