PHP 8.4 | build-phar: remove use of E_STRICT

The `E_STRICT` constant is deprecated as of PHP 8.4 and will be removed in PHP 9.0.

The error level hasn't been in use since PHP 8.0 anyway, so removing the exclusion from the `error_reporting()` setting in the `build-phar` script should make no difference in practice.

Ref:
* https://wiki.php.net/rfc/deprecations_php_8_4#remove_e_strict_error_level_and_deprecate_e_strict_constant

scripts/build-phar.php

@@ -19,7 +19,7 @@
 use PHP_CodeSniffer\Tokenizers\PHP;
 use PHP_CodeSniffer\Util\Tokens;
 
-error_reporting(E_ALL | E_STRICT);
+error_reporting(E_ALL);
 
 if (ini_get('phar.readonly') === '1') {
     echo 'Unable to build, phar.readonly in php.ini is set to read only.'.PHP_EOL;