Add changelog for confighttp ErrorLog update (#12172)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description
Added Zap as the default error logger in `confighttp.ToServer()` to
ensure consistency in logging and to prevent errors from being printed
using a different logger. This change configures the `ErrorLog` field of
the `http.Server` to use a logger backed by Zap, which is initialized
with the provided logger in `TelemetrySettings`. If the logger creation
fails, the function now returns `nil, err` to prevent any undefined
behavior from occurring due to an incomplete setup of the logger.

<!-- Issue number if applicable -->
#### Link to tracking issue
Fixes #11820


<!--Describe the documentation added.-->
#### Documentation
Updated the changelog with information regarding the new default error
logger for `confighttp`. Added details to internal documentation to
reflect the change and ensure proper usage of the new logging system in
server configuration.

Author: sonalgaud12

.chloggen/confighttp-errorlog-update.yaml

@@ -0,0 +1,13 @@
+change_type: bug_fix
+
+component: confighttp
+
+note: "confighttp.ToServer now sets ErrorLog with a default logger backed by Zap"
+
+issues: [11820]
+
+subtext: |
+
+  This change ensures that the http.Server's ErrorLog is correctly set using Zap's logger at the error level, addressing the issue of error logs being printed using a different logger.
+
+change_logs: []

config/confighttp/confighttp.go

@@ -18,6 +18,8 @@ import (
 	"github.com/rs/cors"
 	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"go.opentelemetry.io/otel"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 	"golang.org/x/net/http2"
 	"golang.org/x/net/publicsuffix"
 
@@ -489,15 +491,21 @@ func (hss *ServerConfig) ToServer(_ context.Context, host component.Host, settin
 		includeMetadata: hss.IncludeMetadata,
 	}
 
+	errorLog, err := zap.NewStdLogAt(settings.Logger, zapcore.ErrorLevel)
+	if err != nil {
+		return nil, err // If an error occurs while creating the logger, return nil and the error
+	}
+
 	server := &http.Server{
 		Handler:           handler,
 		ReadTimeout:       hss.ReadTimeout,
 		ReadHeaderTimeout: hss.ReadHeaderTimeout,
 		WriteTimeout:      hss.WriteTimeout,
 		IdleTimeout:       hss.IdleTimeout,
+		ErrorLog:          errorLog,
 	}
 
-	return server, nil
+	return server, err
 }
 
 func responseHeadersHandler(handler http.Handler, headers map[string]configopaque.String) http.Handler {