Update the text wrapping API.

1) Update the LineBreakConfig class to be immutable.
2) Do not return null in the PrecomputedText.Params#getLineBreaiConfig API

Bug: 216638444
Test: atest TextViewTest; atest MeasuredTextTest; atest PrecomputedTextTest; atest TextViewPrecomputedTextTest; atest StaticLayoutLineBreakingVariantsTest
Merged-In: I93bcb6ebc35344e34e9bb8a24df375aa7b3a8d81
Merged-In: I07766137ff6639c7d4acaad07dbcf11a2841cdb0
Change-Id: I07766137ff6639c7d4acaad07dbcf11a2841cdb0
6 files changed