refactor(auth): Centralize logging for saving credentials

The logic for logging the path where credentials are saved was duplicated across several client implementations.

This commit refactors this behavior by creating a new centralized function, `misc.LogSavingCredentials`, to handle this logging. The `SaveTokenToFile` method in each authentication token storage struct now calls this new function, ensuring consistent logging and reducing code duplication.

The redundant logging statements in the client-level `SaveTokenToFile` methods have been removed.

internal/misc/credentials.go

@@ -0,0 +1,16 @@
+package misc
+
+import (
+	"path/filepath"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// LogSavingCredentials emits a consistent log message when persisting auth material.
+func LogSavingCredentials(path string) {
+	if path == "" {
+		return
+	}
+	// Use filepath.Clean so logs remain stable even if callers pass redundant separators.
+	log.Infof("Saving credentials to %s", filepath.Clean(path))
+}