Spacer: Adjust to inherit display and flex properties

[yogeshbhutkar]

What, Why and How?

Fixes: #68889

This PR addresses a bug where the Spacer block fails to fill the available space when the height is set to "Grow" within a stack block with a defined minimum height. Instead of expanding, the Spacer block's height incorrectly becomes 0.

Testing Instructions

1. Create a stack block.
2. Set the minimum height of the block to 500px.
3. Add a spacer block within it.
4. Set the height of the spacer block to Grow.
5. Observe the height properly reflects the available space.

Screenshots or screencast

Screen.Recording.2025-01-27.at.1.22.23.PM.mov

Before	After

[github-actions]

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[yogeshbhutkar]

I believe the failing tests are unrelated to the changes introduced in this PR.