[Panel & Flow Item] Add `"content-bottom"` slot

[geospatialem]

Check existing issues

• [X] I have checked for existing issues to avoid duplicates

Description

Add a new slot to the panel and flow-item components - "content-bottom" so we can render in new a Dialog component using the "sticky" functionality currently provided in the Modal component.

Acceptance Criteria

1. Slot should be sticky as it is Modal
2. Slot should come with overridable padding
3. The following css vars should be added to match Modal's current overrides: --calcite-panel-content-bottom-padding: Specifies the padding of the component's content-bottom slot --calcite-panel-content-background: Specifies the background color of content placed in the component's "content" slot

Relevant Info

A dependency needed for the Dialog + Modal component effort in #7886 See Figma file for specs

Which Component

panel flow-item

Example Use Case

No response

Priority impact

p2 - want for current milestone

Calcite package

• [X] @esri/calcite-components
• [ ] @esri/calcite-components-angular
• [ ] @esri/calcite-components-react
• [ ] @esri/calcite-design-tokens
• [ ] @esri/eslint-plugin-calcite-components

Esri team

Calcite (design)

[github-actions[bot]]

cc @geospatialem, @brittneytewks

[github-actions[bot]]

Installed and assigned for verification.

[DitwanP]

Moving back to in development to include changes to flow-item as well.

[github-actions[bot]]

Installed and assigned for verification.

[github-actions[bot]]

Installed and assigned for verification.

[DitwanP]

🍡Verified on 2.9.0-next.18