Resolve "Remove button row from environments empty state"

What does this MR do?

This MR includes minor improvements to the Environments empty state:

• Remove the duplicate CTA button from the empty state message.
• Update the CTA help link copy to comply with the Pajamas guidelines.

Out of scope

This MR does not include:

• Removing the tabs and if no environments at all.
• Illustration when empty state is displayed.

Screenshots

No available environments	No stopped environments

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

Closes #24324 (closed)