docs(main-detail-container): move configuration controls into card

[spike-rabbit]

Aligns with many other examples we have.

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Documentation.
Examples.
Dashboards Demo.
Playwright report.

Coverage Reports:

• charts-ng
• dashboards-ng
• element-ng
• element-translate-ng
• maps-ng
• native-charts-ng

[gemini-code-assist]

Code Review

This pull request refactors the settings forms in the main-detail container examples to use si-form-item components and ngModel bindings, importing FormsModule and SiFormItemComponent in the process. Feedback highlights an invalid [ngModel] property binding in si-main-detail-container-block.html that will cause a compilation error, as well as violations of the Siemens UX writing guidelines regarding capitalization for the 'Resizable Parts' labels, which should be in sentence case ('Resizable parts').

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