cmd/geth: allow configuring metrics HTTP server on separate endpoint (#21290)

Exposing /debug/metrics and /debug/metrics/prometheus was dependent
on --pprof, which also exposes other HTTP APIs. This change makes it possible
to run the metrics server on an independent endpoint without enabling pprof.

mobile/geth.go

@@ -113,7 +113,7 @@ func NewNode(datadir string, config *NodeConfig) (stack *Node, _ error) {
 	}
 
 	if config.PprofAddress != "" {
-		debug.StartPProf(config.PprofAddress)
+		debug.StartPProf(config.PprofAddress, true)
 	}
 
 	// Create the empty networking stack