Image block: Rename $p variable to $processor

[ockham]

What?

In the Image block's PHP code, rename the $p variable to $processor.

Why?

See #71893 (comment):

this looks like existing code, but it would be nice to rename $p here to $processor for consistency with other code in Core as example code.

How?

Simple replace.

Testing Instructions

Should be covered by unit and e2e tests. Some manual smoke testing of the Image block (on the frontend) won't hurt, though.

[fabiankaegy]

Looks good to me 👍 All instances have been updated

[github-actions]

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Co-authored-by: ockham <bernhard-reiter@git.wordpress.org>
Co-authored-by: fabiankaegy <fabiankaegy@git.wordpress.org>
Co-authored-by: cbravobernal <cbravobernal@git.wordpress.org>

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[github-actions]

Flaky tests detected in e656d4c.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/18192410273
📝 Reported issues:

• [Flaky Test] should refresh the page when stylesheet loading fails #71722 in /test/e2e/specs/interactivity/router-styles.spec.ts