Joplin UI: Create content model & Contact modal

"As a city author, I need the authoring experience to have a logical visual hierarchy so that I am better able to understand the **Create content model & Contact modal** interface." - A City Author

This is a broken out section of the Joplin UI re-design.

#### Acceptance Criteria
- [ ] Matches styles from XD Design 👇
- ~https://xd.adobe.com/view/c533a077-9314-46a6-5db4-d4a7f8601e8f-b302/screen/c6be893c-a72a-4714-bc90-d7ab660d361d/Joplin-3-Phase-1-enhancements-Pages-tab-2~
- Update: we recently redesigned this component in #4314. Abstract branch: [🚧 "Create content” modal enhancements](https://share.goabstract.com/267df4b3-1101-46d1-a759-7629470080e7)
- [ ] Matches CSS for Themes and Colors from Google doc 👇 "Phase 1 acceptance criteria"
- See Create content model section: https://docs.google.com/document/d/1SdAro51Ppdi3Hirn1XkVviJ6nu89dDXtvvFKIX4T8t8/edit#heading=h.gm0g04lqxo5i
- Also, Contact modal section: https://docs.google.com/document/d/1SdAro51Ppdi3Hirn1XkVviJ6nu89dDXtvvFKIX4T8t8/edit#heading=h.hr0v628ofrcp

#### Technical Acceptance Criteria
- [ ] Matches any new structural patterns implemented into the new Joplin UI
- [ ] Checks for and removes any dead-css no longer being used.

Start by reviewing the redesign context in issue #4314, then compare the Create content model and Contact modal against the linked XD, Abstract, and Google Docs designs. Done means the UI matches the referenced styles, themes, colors, and structural patterns, with unused CSS removed.

Written by the indexing model from the issue text.