[Popover] Update the spec for IOS

[Bibisirius]

For the iOS Popover, here’s the summary:

iOS will provide helpers, but ultimately, we will need to use the native component.

Position:

• The position will be automatic, meaning we can’t predict its appearance location natively. However, we can override this if necessary

Intent:

• We can change the intents if needed

Content:

• Content management is handled by the user by default. If there’s a need to add a close button or other buttons, it will be the user's responsibility

Size:

• There’s no option to control its size. Users will need to manage this themselves

Design:

• No blocking points

• We’ll need to add some warnings in the specs about position and content for example, and indicate in the ZH list "Native + Helper"

Swift UI:

• We can only change the color