fix(high text contrast): revert name back to "High Text Contrast"

We're holding off on launching High Contrast Text improvements,
so we're reverting back to the original name to avoid user confusion.

We'll save the name change for when we change the appearance of the
feature.

Bug: 344028969
Flag: ACONFIG com.android.settings.accessibility.enable_color_contrast_control NEXTFOOD
Flag: ACONFIG com.android.graphics.hwui.flags.high_contrast_text_small_text_rect STAGING
Test: manual
Change-Id: Icadf1b708b42f684b0d93a59bb7ff8dab26807dd