[WFCORE-7030] Upgrade Undertow to 2.3.18.Final

[fl4via]

Jira: https://issues.redhat.com/browse/WFCORE-7030

26.x PR: #6220

    Release Notes - Undertow - Version 2.3.18.Final

Bug

• [UNDERTOW-2333] - Undertow read/write timeout should not apply to WebSockets or SSE
• [UNDERTOW-2412] - Read stored json with default UTF-8 encoding
• [UNDERTOW-2422] - Response Status Line protocol is hard-coded to "HTTP/1.1"
• [UNDERTOW-2436] - Race condition for HttpServerExchange state allows missed FLAG_REQUEST_TERMINATED flag with async requests and subsequent connection stall
• [UNDERTOW-2444] - H2 violation of protocol specification in RST_STREAM scenarios
• [UNDERTOW-2445] - CI Build is broken: actions/upload-artifact v1 and v2 are deprecated
• [UNDERTOW-2446] - HttpServletRequestImpl.getParts may throw exception after already loading parts
• [UNDERTOW-2448] - Broken responses after UNDERTOW-2425

[bstansberry]

Thanks @fl4via