deps: bump WebKit to eb92990ae9e0a8df3141b8cf946a4f250393e213 (#21702)

## Summary
- Updates WebKit from 75f6499 to eb92990 (latest release from
oven-sh/webkit)
- This brings in the latest WebKit improvements and fixes

## Test plan
- [ ] Verify the build completes successfully
- [ ] Run existing test suite to ensure no regressions

🤖 Generated with [Claude Code](https://claude.ai/code)

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

src/bun.js/bindings/ErrorCode.cpp

@@ -303,11 +303,11 @@ void JSValueToStringSafe(JSC::JSGlobalObject* globalObject, WTF::StringBuilder&
     }
     case JSC::JSType::SymbolType: {
         auto symbol = jsCast<Symbol*>(cell);
-        auto result = symbol->tryGetDescriptiveString();
-        if (result.has_value()) {
-            builder.append(result.value());
+        auto result = symbol->description();
+        if (!result.isEmpty()) {
+            builder.append(symbol->tryGetDescriptiveString().value_or(String()));
         } else {
-            builder.append("Symbol"_s);
+            builder.append(globalObject->vm().smallStrings.symbolString());
         }
         return;
     }