[http] discard web socket connection without handler

[linev]

If no any handler was found - http request associated with specified web socket can be directly discarded.

Before connection was established - but was not handled in the ROOT.
Just was consuming resources - civetweb thread.

[dpiparo]

Adding @jblomer in the reviewers pool.

[github-actions]

Test Results

    22 files      22 suites   3d 13h 33m 25s ⏱️
 3 850 tests  3 849 ✅ 0 💤 1 ❌
76 031 runs  76 030 ✅ 0 💤 1 ❌

For more details on these failures, see this check.

Results for commit 01eb7df.

[linev]

/backport to 6.40, 6.38, 6.36, 6.32, 6.30

[root-project-bot]

Preparing to backport PR #22183 to branches 6.40, 6.38, 6.36, 6.32 and 6.30 requested by linev

[root-project-bot]

This PR has been backported to

• Branch 6.40:#[6.40] [http] discard web socket connection without handler #22273
• Branch 6.38:#[6.38] [http] discard web socket connection without handler #22274
• Branch 6.36:#[6.36] [http] discard web socket connection without handler #22275
• Branch 6.32:#[6.32] [http] discard web socket connection without handler #22276
• Branch 6.30:#[6.30] [http] discard web socket connection without handler #22277