Block Bindings: Enable custom blocks in pattern overrides with role: content property

[artemiomorales]

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Experimenting with enabling pattern overrides for custom, dynamic blocks.
Meant to be tested in conjunction with WordPress/gutenberg#66518 — see the PR description there.

This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[github-actions]

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