[Settinglib][UI] fixed introPreference summary and button alignment

- Set minLines to 1 according to the UX spec
- Set default collapsed
- Update Textview alignment to use gravity since width is set to align to parent which make the start/end alignment no use.
- Button is subclass of TextView, so we need to add handle case before the Textview.

Bug: 380277395
Test: manual
Flag: EXEMPT library update
Change-Id: I7bb24fe4b6cf39ff351c26099e3cbc20d5667f0d