Deprecate DPP histogram message and migrate to standard histogram

Deprecate DPP histogram message and migrate to standard histogram.
Field and DPP specific histogram message can be safely removed since
the data has not been aggregated yet.

Bug: 123231626
Test: frameworks/opt/net/wifi/tests/wifitests/runtests.sh
Change-Id: I87622f5016d5b0ef13ac72bccc2f8136a42fd240