Apply BE logic for oidc server logs (#155)

### Description

Apply BE logic for oidc server logs.

### Type of change

* [ ] New feature
* [ ] Feature improvement
* [x] Bug fix
* [ ] Documentation
* [ ] Cleanup / refactoring
* [ ] Other (please explain)


### How is this change tested ?

* [ ] Unit tests
* [x] Manual tests (explain)
* [ ] Tests are not needed

proxy/logging.go

@@ -77,6 +77,13 @@ func (be *Backend) logErrorF(format string, args ...any) {
 	log.Printf(format, args...)
 }
 
+func (be *Backend) logError(args ...any) {
+	if !shouldLog(logError, be.LogFilter, be.defaultLogFilter) {
+		return
+	}
+	log.Print(args...)
+}
+
 func shouldLog(typ logType, f ...LogFilter) bool {
 	if typ == logConnection {
 		for _, ff := range f {
@@ -110,6 +117,10 @@ func (p *Proxy) extLogger() logger {
 	return logger{p.logErrorF, p.logError}
 }
 
+func (be *Backend) extLogger() logger {
+	return logger{be.logErrorF, be.logError}
+}
+
 type logger struct {
 	f1 func(string, ...any)
 	f2 func(...any)

proxy/proxy.go

@@ -505,7 +505,7 @@ func (p *Proxy) Reconfigure(cfg *Config) error {
 					ClaimsFromCtx: claimsFromCtx,
 					Clients:       make([]oidc.Client, 0, len(ls.Clients)),
 					EventRecorder: er,
-					Logger:        p.extLogger(),
+					Logger:        be.extLogger(),
 				}
 				for _, client := range ls.Clients {
 					opts.Clients = append(opts.Clients, oidc.Client{