e2e: Fix Map block test (#95290)

Automattic/jetpack#39708 associated the "Add a location" `<label>` with
the `<input>`, which makes Playwright use that as the accessible name
for the input rather than the input's placeholder.

Switch the test to look for the placeholder specifically, instead of the
name, which will work with both the old and new code.

packages/calypso-e2e/src/lib/blocks/block-flows/map.ts

@@ -47,7 +47,7 @@ export class MapFlow implements BlockFlow {
 			// Enter the supplied address.
 			const editorParent = await context.editorPage.getEditorParent();
 			await editorParent
-				.getByRole( 'textbox', { name: 'Add a marker' } )
+				.getByPlaceholder( 'Add a marker' )
 				.type( this.configurationData.address, { delay: 5 } );
 
 			// Wait for the popover and click on the first matching item.