Subscription Details: fix table styles and skeleton

What does this MR do?

This MR is a quick fix following up this comment on the related MR. It's:

• using a table structure to align the labels and content
• determining how many skeleton loader lines to show, based on the fix amount of details
• update needed implementation and tests

Note that, as described in the MR series, there is no actual visible UI change that will be presented to the user. The screenshots are added as a quick way to check the result.

To see the changes locally

Use Rails console to run:

ApplicationSetting.current.update(cloud_license_enabled: true)

Use the following patches:

• loading: no-data.patch
• loaded: data.patch

Screenshots (strongly suggested)

Desktop

Loading	Loaded

Mobile

Loading	Loaded

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because the feature is behind application flag.
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team