Don't show the caption for BubbleBarExpandedView if overflow.

The overflow view doesn't show a handle or have caption bar insets, so the caption view doesn't need to be visible.

Before: screenshot/5F3X2ZrB9wsTDnj
After: screenshot/AfTGqk6ZrmMXwGU
Bug: 403612933
Test: wm presubmit
Flag: com.android.wm.shell.enable_create_any_bubble
Change-Id: I5626f8832aad2dfc15bf96bc93b3f2cc7e86b496