fix(formatted-string) allow Span descendants in FormattedString (#7370)
fix(formatted-string) allow Span descendants in FormattedString (#7370)

* (fix) Allow Span descendants in FormattedString

Currently FormattedString doesn't allow custom components extending Span to be its children. This small PR fixes that.

Closes #7369.

* Remove the now unused CHILD_SPAN

NativeScript/NativeScript,NativeScript/NativeScript,NativeScript/NativeScript,NativeScript/NativeScript,NativeScript/NativeScript