In some languages, when the text contains a new line "\n", the `v8BreakIterator` starts returning different values from `breakType()`. This caused our code to think that those line breaks were hard line breaks when in fact they were soft line breaks. Still unclear if this is a `v8BreakIterator` bug or a wrong expectation on our side regarding how `breakType()` is supposed to work.
Instead of using `v8BreakIterator.breakType()`, let's do the `soft` vs `hard` detection ourselves (we already have all the necessary pieces).
Fixes https://github.com/flutter/flutter/issues/127379
907fcd3245