Fix: Add line-height to body in editor styles for consistency with frontend

[R1shabh-Gupta]

Trac ticket: https://core.trac.wordpress.org/ticket/63549

This PR addresses a line-height inconsistency between the editor and the frontend. It follows up on [Trac ticket #60196](https://core.trac.wordpress.org/ticket/60196), which resolved margin issues but left a spacing difference due to how line-height is applied in the editor iframe.

[github-actions]

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[github-actions]

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[github-actions]

A commit was made that fixes the Trac ticket referenced in the description of this pull request.

SVN changeset: 60366
GitHub commit: 08a81e7

This PR will be closed, but please confirm the accuracy of this and reopen if there is more work to be done.

[github-actions]

A commit was made that fixes the Trac ticket referenced in the description of this pull request.

SVN changeset: 61106
GitHub commit: 945619c

This PR will be closed, but please confirm the accuracy of this and reopen if there is more work to be done.