[Crawler] Add proper validation of node argument of method add
merged branch entering/crawler-add-node-argument (PR #7924)

This PR was squashed before being merged into the master branch (closes #7924).

Discussion
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[Crawler] Add proper validation of node argument of method add

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

Crawler method add, fix PHPdoc and

Commits
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41805c0 [Crawler] Add proper validation of node argument of method add
fixed CS