Add Text Data to Composition Tree Dump Contents

[chiaramooney]

Currently we have Composition Tree Dump tests which dump some of the contents of a components Composition tree into a JSON object. We should add text data to the JSON dumps, so we have information on text value and styling included in our checks for visual regressions.

[jonthysell]

We should also have rendering verification tests (i.e. screenshot comparisons).

[jonthysell]

We should also decide what we capture in the text comparison (raw text, styling, etc)