feat: support caller skip in logx (#2401)

* feat: support caller skip in logx

* chore: remove debug prints

* chore: remove debug prints

* chore(deps): bump go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc (#2402)

Bumps [go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc](https://github.com/open-telemetry/opentelemetry-go) from 1.9.0 to 1.10.0.
- [Release notes](https://github.com/open-telemetry/opentelemetry-go/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-go/blob/main/CHANGELOG.md)
- [Commits](https://github.com/open-telemetry/opentelemetry-go/compare/v1.9.0...v1.10.0)

---
updated-dependencies:
- dependency-name: go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* chore: simplify test code

* chore: remove new WithFields in logx, and deprecated old WithFields

* chore: simplify WithDuration

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

core/logx/syslog_test.go

@@ -42,11 +42,18 @@ func captureOutput(f func()) string {
 }
 
 func getContent(jsonStr string) string {
-	var entry logEntry
+	var entry map[string]interface{}
 	json.Unmarshal([]byte(jsonStr), &entry)
-	val, ok := entry.Content.(string)
-	if ok {
-		return val
+
+	val, ok := entry[contentKey]
+	if !ok {
+		return ""
 	}
-	return ""
+
+	str, ok := val.(string)
+	if !ok {
+		return ""
+	}
+
+	return str
 }