Remove the special logic for the `device.hasSubtext()` condition.

- `device.hasSubtext()`` should affect only the subtitle rendering,
nothing more.
- Fixes "Expandable and with subtext (subtext breaks stream expansion)"
scenario from b/355062931.

Flag: EXEMPT bugfix
Bug: 355062931
Fix: 355062931
Test: atest SystemUiRoboTests:MediaOutputAdapterTest
    atest SystemUIGoogleRoboRNGTests:MediaOutputAdapterScreenshotTest
Change-Id: I7f074194fa5a09817322ced5a1b2c0ea28e05e29