Fix color contrast in All Apps text by setting the color to onSurfaceVariant

bug: 322293478
Test:
All Apps divider:
before lightTheme: https://drive.google.com/file/d/1MTL1iEX_icYWfT52WeZIgqLK46koLM_s/view?usp=sharing
after lightTheme: https://drive.google.com/file/d/1ME1Gk8bUIXIe1P_Z5pvcpi3VS0_L0mVK/view?usp=sharing
before darkTheme: https://drive.google.com/file/d/1MLcv32M2JWyVqPklMdZLJAkj8KnyXwtB/view?usp=sharing
after darkTheme: https://drive.google.com/file/d/1MJjgP42xgp7SCifHAfREzgWvw6KupvlR/view?usp=sharing
All Apps text:
before light theme:https://drive.google.com/file/d/1MCu6xtpCMCxtDpnAv3fhCDSafBJGX4rx/view?usp=sharing
after light theme:https://drive.google.com/file/d/1M6ilveUw2q0FIlo-NSxt8KEWKRbQvwhk/view?usp=sharing
before dark theme:https://drive.google.com/file/d/1MCOxt9MeWxgN65T2s0OKzybiPu4qI4PD/view?usp=sharing
after dark theme: https://drive.google.com/file/d/1MAXnRmG8NVMu1bCseVWn6GC2322gQ0sX/view?usp=sharing
Flag: None

Change-Id: Iedb12d7b11b215c6668e7b5e6637189da3d67ebc