Run soong-built module-info.json through merger

The merge_module_info_json tool is normally used to merge soong and
make-built module-info.json files. But the soong-built module-info.json
file is actually a list of modules, and the merger is still necessary
to turn that list into a map.

Bug: 389720048
Test: refreshmod
Change-Id: I89e617cc07058561611ea97f9650016a9817d9e5