[DomCrawler]fix #9321 Crawler::addHtmlContent add gbk encoding support

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |  #9321
| License       | MIT
| Doc PR        | n/a

This is solution 1 in https://github.com/symfony/symfony/issues/9321#issuecomment-26508649