[DomCrawler] added support for query string with slash

Link\getUri() failed to return correct uri when current query string contains slash
merged branch nikrou/relative-path-with-slash (PR #7434)

This PR was merged into the 2.1 branch.

Commits
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e6b7515 [DomCrawler] added support for query string with slash

Discussion
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[DomCrawler] added support for query string with slash

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

Link\getUri() failed to return correct uri when current query string contains slash
Test pass on branch 2.1 but fails on master