[Feature Request]: Align Compute Gallery tests to design principles

### Description

The compute/gallery module has the following deployment validation tests:
- common: where the parent gallery module is validated
- images: where the child gallery/images module is validated

For consistency with other modules and as per design guidelines we should have:
- common: where as many features as possible for the parent and children are validated
- min: where only the parent required parameters are validated

This issue is about
- merging existing common and images tests into the common one
- adding the min test