hive: cast ModuleID to string

The pkg/metrics logging hook explicitly wants a string, not a newtype of
string, hence it complained the type of the subsys field for
module-decorated logrus loggers with unformatted loglines like:

Failed to fire hook: type of the 'subsystem' log entry field is not string but cell.ModuleID

Fixes: 2311f3d (treewide: rebase on cilium/hive)

Reported-by: Joe Stringer <joe@cilium.io>
Signed-off-by: David Bimmler <david.bimmler@isovalent.com>

pkg/hive/hive.go

@@ -55,7 +55,7 @@ func New(cells ...cell.Cell) *Hive {
 	// Scope logging and health by module ID.
 	moduleDecorators := []cell.ModuleDecorator{
 		func(log logrus.FieldLogger, mid cell.ModuleID) logrus.FieldLogger {
-			return log.WithField(logfields.LogSubsys, mid)
+			return log.WithField(logfields.LogSubsys, string(mid))
 		},
 		func(hp healthTypes.Provider, fmid cell.FullModuleID) cell.Health {
 			return hp.ForModule(fmid)