Support two line text in AllApps/OnDeviceSearch w/ feature flag

Made separate feature flag for on device search
Add unit test to test twoLine string
- Unit tests for testing newStringThatShouldSupportTwoLineText() in BubbleTextView.java. This class tests a couple of strings
and uses the getLineCount() to determine if the test passes. Verifying with getLineCount() is sufficient since BubbleTextView can only be in one line or two lines,
and this is enough to ensure whether the string should be specifically wrapped onto the second line and to ensure truncation.

bug: 201388851
test: presubmit, ran locally on big and small device, before: https://screenshot.googleplex.com/3Q6pwveFDZqxDXL (ORIGINAL TWO LINE TEXT)
after:  https://screenshot.googleplex.com/7pkwUto6HGzMYoT

Change-Id: I93e6ed179e1081d5cdffc6db9c7ae34de8021c24