[Notif redesign] Update size of top line icons

Increase the size of the icons slightly to match the spec, and make sure
it actually scales with the font size rather than being fixed.

Note that notification_2025_top_line_views is a fork of
notifications_top_line_views.

Bug: 378660052
Fix: 384068957
Test: tested manually, screenshot tests to come later
Flag: android.app.notifications_redesign_templates
Change-Id: I9244e3e9ad62bd89129abd009e5641f71260ec27