Change the type of TrendMicroManagementAccount to string

[trend-eric-pj-wang]

Change the type of TrendMicroManagementAccount to string

Change Summary

• The TrendMicroManagementAccount should be string type. Since the account ID has the possibility of beginning with 0.
• Change to type of variable TrendMicroManagementAccount in every variables.tf.

PR Checklist

• [x] I've read and followed the Contributing Guide.
• Documents/Readmes
  • [ ] Updated accordingly
  • [x] Not required
• Plugins that have versioning
  • [ ] Version bumped and follows Semantic Versioning
  • [x] Not required

Other Notes