fix(select): removed forced overscroll on non-scrollable popovers

[liamdebeasi]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Issue Number: resolves #23971

Originally added in Ionic 3: https://github.com/ionic-team/ionic-v3/blame/2b7292e8a1187351fff9629bcef271d277abb318/src/components/select/select.scss#L7-L15

This allowed non-scrollable popovers to have a rubber band effect on iOS. Testing with a popover on the latest iOS indicates that non-scrollable popovers should not have a rubber band effect. (See https://www.hackingwithswift.com/quick-start/swiftui/how-to-show-a-popover-view for an example).

What is the new behavior?

• Non-scrollable select popovers no longer rubber band
• Note that this does not change behavior of popovers that use ion-content and have forceOverscroll="true".

Does this introduce a breaking change?

• Yes
• No

Other information