Update the button size in the environments list page

Summary

Related discussion: !194374 (comment 2564189516)

Definition of Done

Users will see the medium-sized button groups rather than the smaller-sized ones.

Details

Current	Proposal

• Storybook: https://gitlab-org.gitlab.io/gitlab-ui/?path=/docs/base-button--docs

Implementation guide

Update environments item component to use the default medium size for the actions component. Remove the size prop to use the default.

Roles involved

• Design
• Technical Writing
• Backend
• Frontend
• Test engineering

NOTE: When work is ready to be defined, please create appropriate sub-tasks.