feat(segment-button): Add --indicator-height property to segment button

[nikosdouvlis]

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?

Each ion-segment-button inside an ion-segment has an indicator right below it with a height of 2px. You can customize the color of the indicator but not the height.

What is the new behavior?

Setting the --indicator-height css variable on an ion-segment-button sets its height. The default value is 2px.

Does this introduce a breaking change?

• Yes
• No

[brandyscarney]

Thank you for the PR! I'm working on some big changes to segment right now as part of this but I will get this in: #19036. 🙂