Fix quoted WebSocket extension parameters

[liyifan9642-creator]

Closes #37284

WebSocket extension parameters may use quoted-string syntax. The current parser splits values without tracking quoted sections and leaves quoted values encoded.

This change:

• tokenizes extension and parameter lists while respecting quoted strings and quoted-pair escapes;
• unquotes extension parameter values;
• enforces RFC 6455's requirement that the unescaped value conform to the token ABNF;
• rejects malformed or unterminated quoted values.

Tests cover valid quoted values, quoted-pair unescaping, invalid decoded token values, and unterminated quoted strings.

Validation:

• ./gradlew :spring-websocket:test
• ./gradlew :spring-websocket:checkstyleMain :spring-websocket:checkstyleTest

All 399 spring-websocket tests pass.