Fixes broken Site Title selector in Gutenberg 19.2.

Gutenberg 19.2 broke `theme.json` styles on the Site Title block by changing the selector to specifically target the link rather and not the block itself. This change reverts that selector to its original state.

See: WordPress/gutenberg#64911

src/Block/Metadata.php

@@ -265,6 +265,20 @@ private function coreQueryPagination(array $settings): array
 		return $settings;
 	}
 
+	/**
+	 * Fixes the broken selector introduced in Gutenberg 19.2.
+	 *
+	 * @since 1.0.0
+	 * @link  https://github.com/WordPress/gutenberg/pull/64911
+	 */
+	private function coreSiteTitle(array $settings): array
+	{
+		$settings['selectors']               ??= [];
+		$settings['selectors']['typography']   = '.wp-block-site-title';
+
+		return $settings;
+	}
+
 	/**
 	 * Adds color support to the Tag Cloud block.
 	 *