FP3: wifi: Remove IWifi hidl entry from manifest.xml

This CL removes the definition for the IWifi hidl interface from
manifest.xml and rely on vint-fragements entry.
This is to avoid the need to modify the revision in future

Bug: 138243400
Test: builds and wifi works
Change-Id: Icaff93193e10d4953d9947d2739b05959ece79f1