Removed experiments to work with new terraform version

[azhar22k]

Description

experiments = [variable_validation] as it breaks with Terraform v0.13.0 which has this inbuilt and when set explicitly, gives error

Error: Experiment has concluded

  on .terraform/modules/tags/tags/variables.tf line 3, in terraform:
   3:   experiments = [variable_validation]

Experiment "variable_validation" is no longer available. Custom variable
validation can now be used by default, without enabling an experiment.

Description of what this PR does. What have you added or changed, and why?

• Bug Fix
• Enhancement (new features, refinement)
• Breaking Change
• Refactor
• Documentation

Steps to test

1. Try terraform init on an infra with tags modules used along with Terraform CLI v0.13.0