refactor: remove superfluous type checks

Types are now checked at function call, so we can assume the type is
always correct at time of execution.

src/Helpers/InterfaceHelper.php

@@ -34,7 +34,7 @@ public static function class_implements_interface( string $class_name, string $i
 	 * @return bool
 	 */
 	public static function class_implements_interfaces( string $class_name, array $interfaces ): bool {
-		if ( ! is_string( $class_name ) || ! class_exists( $class_name ) ) {
+		if ( ! class_exists( $class_name ) ) {
 			return false;
 		}
 

src/Helpers/Settings.php

@@ -114,10 +114,6 @@ public static function get_option( string $option_name, string $type = 'general'
 	 * @return null|mixed Value at given path, if present.
 	 */
 	public static function get_array_value_by_path( string $path, array $array ) {
-		if ( ! is_array( $array ) ) {
-			return null;
-		}
-
 		$path_array = self::get_path_parts( $path );
 		if ( empty( $path_array ) ) {
 			return null;