freeling: remove icu dependency

[ryandesign (Ryan Carsten Schmidt)]

freeling declares a library dependency on icu, but it doesn't seem to actually be used. freeling's configure script does check for the presence of the icuuc library, but doesn't seem to do anything with it. The files installed by freeling do not link with any icu library. It does link with boost libraries, and boost does link with and declare a library dependency on icu, so icu will definitely be present when freeling is being built, but the library dependency on icu declared in the freeling port made me think I would need to increase the revision of freeling when I update icu to a new version, which seems not to be the case after all.

[ryandesign (Ryan Carsten Schmidt)]

In 867d599/macports-ports:

freeling: Remove icu dependency

Closes: #47437