Tidy license page to meet style standards

What does this MR do?

Updates https://docs.gitlab.com/ee/user/admin_area/license.html to:

• Fix tone and style
• Reflow a note back into the main text
• Strip out future tense
• Remove a screenshot of the UI that's old enough to not have a version number, and replace it with the direct link to the SVG icon the screenshot was trying to pinpoint

No major changes to content.

cc @s_awezec @jeromezng for awareness. Sending to Evan for a quick tone / style review.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• 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