[webgui] strict check for HMAC signature [6.32]

[linev]

Prevent situation with manipulated packet send without HMAC at all could be accepted

[github-actions[bot]]

Test Results

     9 files       9 suites   1d 16h 13m 10s :stopwatch:  2 629 tests  2 629 :white_check_mark: 0 :zzz: 0 :x: 22 109 runs  22 109 :white_check_mark: 0 :zzz: 0 :x:

Results for commit 6a5f1782.