function facetAwareSegment(text, length, facets)
Segment a string into substrings of a given grapheme length, without breaking facets.
Parameters
text: string
The string to segment.
length: number
The maximum grapheme length of each segment.
facets: AppBskyRichtextFacet.Main[]
The facets to avoid breaking.
Returns
{ facets: AppBskyRichtextFacet.AppBskyRichtextFacet.Main[]; text: string; }[]
An array of substrings and their associated facets.