Update clickhouse backup to use cluster variable

[VictorSilvaOliveira]

Update clickhouse backup to use cluster variable configured on values.yaml

Description

Update clickhouse backup to use cluster variable configured on values.yaml

Type of change

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

How has this been tested?

Checklist

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works