[MMA-17623] - adding skip tag for c3 next gen host count validation

[nagarwal01]

Description

C3 next gen can run on multiple hosts, this is required for High Availability Setups.
Added a new variable for skipping validation skip_control_center_next_gen_host_count_validation

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• without skip variable, validation error 🔴

• with skip_control_center_next_gen_host_count_validation = true var, No validation error ✅

vars:
    skip_control_center_next_gen_host_count_validation: true

Checklist:

• Any variable/code changes have been validated to be backwards compatible (doesn't break upgrade)
• I have added tests that prove my fix is effective or that my feature works
• If required, I have ensured the changes can be discovered by cp-ansible discovery codebase
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[rkunwar-28]

LGTM, thanks!