Callers use ISourceText instead of IRawText or IRawTextProvider.
Model service holds the ownership of IRawText, Creation options and resolved options for model

 - model creation options can now be specified at a later stage

Only skip the string height measurement if the variable has children (is an object/array) or has a name (is a prop of an object/array)

Fixes #17146.

Fix #19524

Fixes #19204

Fixes #18833