Add descriptions of LawLogix and Modern Health integrations

Why is this change being made?

Keep the handbook up-to-date with our recently added integrations

closes https://gitlab.com/gitlab-com/business-technology/enterprise-apps/integrations/platypus/-/issues/210

closes https://gitlab.com/gitlab-com/business-technology/enterprise-apps/integrations/platypus/-/issues/211

Author Checklist

• Provided a concise title for this Merge Request (MR)
• Added a description to this MR explaining the reasons for the proposed change, per say why, not just what
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• If the changes affect team members, or warrant an announcement in another way, please consider posting an update in #whats-happening-at-gitlab linking to this MR
  • If this is a change that directly impacts the majority of global team members, it should be a candidate for #company-fyi. Please work with internal communications and check the handbook for examples.

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