python3Packages.openapi-spec-validator: add missing dependency on openapi-schema-validator

[AluisioASG]

Add a new dependency introduced in 0.2.10 (or 0.3.0 since we updated straight to that).

Motivation for this change

Trying to unbreak #120447.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[r-rmcgibbo]

Result of nixpkgs-review pr 120793 at 2e8fcd22 run on x86_64-linux 1

5 packages failed to build:

• apache-airflow
• python38Packages.connexion
• python38Packages.flask-appbuilder
• python39Packages.connexion
• python39Packages.flask-appbuilder

10 packages built successfully:

• python38Packages.apispec
• python38Packages.openapi-schema-validator
• python38Packages.openapi-spec-validator
• python38Packages.prance
• python38Packages.rfc3339-validator
• python39Packages.apispec
• python39Packages.openapi-schema-validator
• python39Packages.openapi-spec-validator
• python39Packages.prance
• python39Packages.rfc3339-validator

Note that build failures may predate this PR, and could be nondeterministic or hardware dependent.
Please exercise your independent judgement.

---

Result of nixpkgs-review pr 120793 at 2e8fcd22 run on aarch64-linux 1

5 packages failed to build:

• apache-airflow
• python38Packages.connexion
• python38Packages.flask-appbuilder
• python39Packages.connexion
• python39Packages.flask-appbuilder

10 packages built successfully:

• python38Packages.apispec
• python38Packages.openapi-schema-validator
• python38Packages.openapi-spec-validator
• python38Packages.prance
• python38Packages.rfc3339-validator
• python39Packages.apispec
• python39Packages.openapi-schema-validator
• python39Packages.openapi-spec-validator
• python39Packages.prance
• python39Packages.rfc3339-validator

Note that build failures may predate this PR, and could be nondeterministic or hardware dependent.
Please exercise your independent judgement.

[AluisioASG]

• connexion is incompatible with openapi-spec-validator 0.3.x: Connexion incompatible with openapi-spec-validator==0.3.0 spec-first/connexion#1343
• flask-appbuilder seems to be missing a matching version of flask-jwt-extended, which from what I'm seeing we already provide actually we don't (since Python packages set: major upgrades #117452) but search.nixos.org doesn't show it was updated; fix: Upgrade flask_jwt_extended and PyJWT to the latest versions dpgaspar/Flask-AppBuilder#1610 should make it work again
• apache-airflow depends on flask-appbuilder