[RONs] Fix ToplineView end margin

ToplineView is in a relativelayout and aligned to the expander. When expander is not visible, it is aligned to parent's end.
This CL fix this issue by setting correct margin values.
Test: Post a ron with a large subtext to make topline width high. Observe it has enough margin end. Repeat it with largeicon.
Bug: 407819104
Flag: android.app.ui_rich_ongoing

Change-Id: Icfd4b5920d4e8b0667a94131b2a8126d96e0ce46