Fix DynamicLayout init to use transformed text length.

It already uses the transformed text characters, but uses the length of
the base text. This does not account for TransformationMethod2, which
can change length, including AllCapsTransformationMethod ("ß" becomes
"SS") and TranslationTransformationMethod (arbitrary length changes).

This change does not fix updates that happens through
DynamicLayout.ChangeWatcher; those will be fixed in separate change(s).

Bug: 178650596
Test: atest DynamicLayoutBlocksTest DynamicLayoutTest TextLayoutTest \
  TextViewTest
Test: manually on a sample app with AllCaps
Test: manually with Translate on a real app
Change-Id: Iec4699c8d9967cb4622fe59ba91849642d72b52e