Revert isExperimentalBuild removal on registration

The conditional `isExperimentalBuild` conditional check that was
wrapping some conditional registration of the classic template
block seems to be  unrelated to the template conversion/migration.

This is something we can revisit and test separately but should not be
included in this changeset.

assets/js/blocks/classic-template/index.tsx

@@ -7,7 +7,10 @@ import {
 	unregisterBlockType,
 } from '@wordpress/blocks';
 import type { BlockEditProps } from '@wordpress/blocks';
-import { WC_BLOCKS_IMAGE_URL } from '@woocommerce/block-settings';
+import {
+	isExperimentalBuild,
+	WC_BLOCKS_IMAGE_URL,
+} from '@woocommerce/block-settings';
 import { useBlockProps } from '@wordpress/block-editor';
 import { Button, Placeholder } from '@wordpress/components';
 import { __ } from '@wordpress/i18n';
@@ -207,46 +210,55 @@ const registerClassicTemplateBlock = ( {
 
 let currentTemplateId: string | undefined;
 
-subscribe( () => {
-	const previousTemplateId = currentTemplateId;
-	const store = select( 'core/edit-site' );
-	currentTemplateId = store?.getEditedPostId() as string | undefined;
-
-	if ( previousTemplateId === currentTemplateId ) {
-		return;
-	}
-
-	const parsedTemplate = currentTemplateId?.split( '//' )[ 1 ];
-
-	if ( parsedTemplate === null || parsedTemplate === undefined ) {
-		return;
-	}
-
-	const block = getBlockType( BLOCK_SLUG );
-
-	if (
-		block !== undefined &&
-		( ! hasTemplateSupportForClassicTemplateBlock(
-			parsedTemplate,
-			TEMPLATES
-		) ||
-			isClassicTemplateBlockRegisteredWithAnotherTitle(
-				block,
-				parsedTemplate
-			) )
-	) {
-		unregisterBlockType( BLOCK_SLUG );
-		currentTemplateId = undefined;
-		return;
-	}
-
-	if (
-		block === undefined &&
-		hasTemplateSupportForClassicTemplateBlock( parsedTemplate, TEMPLATES )
-	) {
-		registerClassicTemplateBlock( {
-			template: parsedTemplate,
-			inserter: true,
-		} );
-	}
-} );
+if ( isExperimentalBuild() ) {
+	subscribe( () => {
+		const previousTemplateId = currentTemplateId;
+		const store = select( 'core/edit-site' );
+		currentTemplateId = store?.getEditedPostId() as string | undefined;
+
+		if ( previousTemplateId === currentTemplateId ) {
+			return;
+		}
+
+		const parsedTemplate = currentTemplateId?.split( '//' )[ 1 ];
+
+		if ( parsedTemplate === null || parsedTemplate === undefined ) {
+			return;
+		}
+
+		const block = getBlockType( BLOCK_SLUG );
+
+		if (
+			block !== undefined &&
+			( ! hasTemplateSupportForClassicTemplateBlock(
+				parsedTemplate,
+				TEMPLATES
+			) ||
+				isClassicTemplateBlockRegisteredWithAnotherTitle(
+					block,
+					parsedTemplate
+				) )
+		) {
+			unregisterBlockType( BLOCK_SLUG );
+			currentTemplateId = undefined;
+			return;
+		}
+
+		if (
+			block === undefined &&
+			hasTemplateSupportForClassicTemplateBlock(
+				parsedTemplate,
+				TEMPLATES
+			)
+		) {
+			registerClassicTemplateBlock( {
+				template: parsedTemplate,
+				inserter: true,
+			} );
+		}
+	} );
+} else {
+	registerClassicTemplateBlock( {
+		inserter: false,
+	} );
+}