Update Window Header Text Font & Position

Aligned the app name text, app icon, and expand icon positions to be consistent with window header spec. Set the app name text’s font to be “GM3/ Title / Small” (TextAppearance.Material.Title). Changed expand more icon’s drawable to be consistent with launcher’s (ic_expand_more.xml).

Since Header background color and icon colors are still being decided
upon, only the app name font and the app/text/icon alignment aspects of
the spec above are addressed in this CL.

Test: Manual
Bug: 298199770
Change-Id: I63fb223c39a754b3f67cc814a863152e484b3c7a