[ENT-986] Update DSC text to match new enterprise welcome text.

*Description:* This changes the DSC text to match what is now on several other pages.

*JIRA:* https://openedx.atlassian.net/browse/ENT-986

*Merge deadline:* Anytime

*Testing instructions:*

1. Go to the DSC page for a customer that has enabled DSC, and notice this change.

*Merge checklist:*

• [ ] Check that the versions of the requirements in the `platform-master.in` file match edx-platform.

• [ ] New requirements are in the right place (`base.in` if only used in enterprise; in the correct `platform-****.in` files if they're hosted in edx-platform)

• [ ] Regenerate requirements with `make upgrade && make requirements` (and make sure to fix any errors).
  *DO NOT* just add dependencies to `requirements/*.txt` files.

• [ ] Called `make static` for webpack bundling if any static content was updated.

• [ ] All reviewers approved

• [ ] CI build is green

• [ ] Version bumped

• [ ] Changelog record added

• [ ] Documentation updated (not only docstrings)

• [ ] Commits are (reasonably) squashed

• [ ] Translations are updated

• [ ] PR author is listed in AUTHORS

*Post merge:*

• [ ] Create a tag

• [ ] Check new version is pushed to PyPi after tag-triggered build is finished.

• [ ] Delete working branch (if not needed anymore)

• [ ] edx-platform PR (be sure to include edx-platform requirements upgrades that were present in this PR)