[backport#18417 3/3] tests: Add fuzzing harness for functions in net_permissions.h

Summary:
https://github.com/bitcoin/bitcoin/pull/18417/commits/4308aa67e3ea38e3fe5ac84e38a29df36c0d0e10

Depends on D7134

Concludes backport of Core PR18417

Test Plan:

cmake -GNinja .. -DENABLE_SANITIZERS="address;fuzzer" -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
ninja bitcoin-fuzzers
./src/test/fuzz/net_permissions

Reviewers: #bitcoin_abc, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Differential Revision: https://reviews.bitcoinabc.org/D7135