Only run search edu when enabled, also make code more generic.

We only need to run the Search edu if it is enabled on devices. The code
itself is also made more generic in terms of method and variable names.

Fix: 330401405
Test: Enable and disable the search function and check whether the edu tooltip shows
up for each specific use case.
Flag: ACONFIG com.android.launcher3.enable_taskbar_pinning NEXTFOOD

Change-Id: I1cea3ee56922c0b47ae7e8379aad4b36570daa17