fix(logger): Avoid setting the log-format default too early (#16108)

config/config.go

@@ -123,7 +123,6 @@ func NewConfig() *Config {
 			Interval:                   Duration(10 * time.Second),
 			RoundInterval:              true,
 			FlushInterval:              Duration(10 * time.Second),
-			LogFormat:                  "text",
 			LogfileRotationMaxArchives: 5,
 		},
 

logger/logger.go

@@ -227,6 +227,10 @@ func SetupLogging(cfg *Config) error {
 		return fmt.Errorf("invalid deprecated 'logtarget' setting %q", cfg.LogTarget)
 	}
 
+	if cfg.LogFormat == "" {
+		cfg.LogFormat = "text"
+	}
+
 	if cfg.Debug {
 		cfg.logLevel = telegraf.Debug
 	}