Prevent disabling Preview button when the post is not saveable.

This is ripple effect of adding isPostLocked check in `isEditedPostSaveable` selector from 1dfe125. We can safely remove this check on `Preview` button, because #32341 will prevent any save actions under the hood.

packages/editor/src/components/post-preview-button/index.js

@@ -106,7 +106,7 @@ export default function PostPreviewButton( {
 	role,
 	onPreview,
 } ) {
-	const { postId, currentPostLink, previewLink, isSaveable, isViewable } =
+	const { postId, currentPostLink, previewLink, isViewable } =
 		useSelect( ( select ) => {
 			const editor = select( editorStore );
 			const core = select( coreStore );
@@ -119,7 +119,6 @@ export default function PostPreviewButton( {
 				postId: editor.getCurrentPostId(),
 				currentPostLink: editor.getCurrentPostAttribute( 'link' ),
 				previewLink: editor.getEditedPostPreviewLink(),
-				isSaveable: editor.isEditedPostSaveable(),
 				isViewable: postType?.viewable ?? false,
 			};
 		}, [] );
@@ -168,7 +167,6 @@ export default function PostPreviewButton( {
 			className={ className || 'editor-post-preview' }
 			href={ href }
 			target={ targetId }
-			disabled={ ! isSaveable }
 			onClick={ openPreviewWindow }
 			role={ role }
 		>